https://www.theatlantic.com/magazine/archive/1989/08/the-real-war-1939-1945/306374/
They (American soldiers) knew that despite the advertising and publicity, where it counted their arms and equipment were worse than the Germans'. They knew that their automatic rifles (First World War vintage) were slower and clumsier, and they knew that the Germans had a much better light machine gun. They knew, despite official assertions to the contrary, that the Germans had real smokeless powder for their small arms and that they did not. They knew that their own tanks, both American and British, were ridiculously underarmed and underarmored, so that they would inevitably be destroyed in an open encounter with an equal number of German panzers. They knew that the anti-tank mines supplied to them became unstable in subfreezing weather, and that truckloads of them blew up in the winter of 1944-1945. And they knew that the single greatest weapon of the war, the atomic bomb excepted, was the German 88-mm flat-trajectory gun, which brought down thousands of bombers and tens of thousands of soldiers. The Allies had nothing as good, despite the fact that one of them had designated itself the world's greatest industrial power. The troops' disillusion and their ironic response, in song and satire and sullen contempt, came from knowing that the home front then could (and very likely historiography later would) be aware of none of these things.
Huh, strange claim they are going with. I'm on phone at the moment, so I'll come back later to update my comment with references.
There are a couple of things going on here.
At the infantry level, there was a doctrinal difference between the Germans and Americans. Germany built their infantry squads around the machine gun, with the fire-power from the attached infantry being supplemental/tertiary. The US on the other hand put a lot more weight on the impact of rifle fire, in no small part because they had the industrial capacity to hand out semi automatics to pretty much everyone and keep them supplied with ammunitions.
The US just didn't have the demand in the way they built their army for a light machine-gun better than the M1919, as light machine-guns just didn'tplay a big role in how they thought they should fight the war. They were more than capable of making modern high quality small arms, the Grannd is very well regarded, and if you look at machine-guns the the US had a doctrinal use for, such as the M2, they made highly effective/competitive machine guns.
It is a similar story with the Pak 43. The US, and for the most part the allies didn't have a doctrinal need for large amounts of modern anti air cannons. Instead they were either at no risk of being bombed or instead made aggressive use of radar directed fighter cover for air defence. The US made a range of anti aircraft cannons in the style of the Pak 43 (the M1, 2 & 3 90mm gun) they just didn't really need them to combat German airraids in the same way the Germans did.
If he is talking about use as an anti tank weapon, again doctrinal difference. The US built their army including the ideal of the tank destroyer battalion would the primary tool to combat Axis armour. In practice it was not as effective as you the US had hopped it would be, but in terms of weaponry built for it, with the m36 being a highly effective anti tank weapon.
No clue what he his going on about claiming the US didn't have smokeless powder.
Then we get to the classic claim that Panzers . This has already been covered in the past so I'll just link to them https://www.reddit.com/r/AskHistorians/comments/372kqy/were_german_tanks_in_wwii_actually_as_far/
To be fair, the article seems to be more talking about perceived view of some service men. If that is the lenses that is being applied pretty much every army in history has been pacing foes with more & better equipment and outnumber their foes.
The very short answer is "no." The longer answer is "not across the board" plus a lot more prevaricating. A couple of things to start off with.
First, it's important to remember context when evaluating claims. The Atlantic is not a history-focused publication and the article is not focused on a comparison of equipment. It is about the experience of front line military personnel and the depictions of that experience that make it back home. In situations like that, it's more likely the author will take liberties with historical "facts" first rhetorical purposes than if an article were written about equipment for an audience well versed in military history.
Second, it's almost impossible to evaluate "better" or "inferior" in absolute terms. In the WWII context, take the two most iconic planes of the war: the Spitfire and the Zero. The Spitfire had a higher top speed, higher ceiling, better rate of climb, (generally) carried heavier armament, and was far less likely to explode when hit with enemy fire. Does that make the Spitfire better? For the British almost certainly yes. For the Japanese almost certainly not, because the Spitfire's relatively short range would have been much more limiting in the vast distances of the Pacific Theater.
To get to the meat of the question, no, American/Allied equipment was not drastically inferior. It seems like the author is taking some examples of impressive German weapons (the MG42, Panzer V and VI, and German 88) and using those to imply that German weapons were superior across the board. That isn't a realistic assessment.
To take an easy example (and contrary to the author's assertion that the US used WWI era rifles) the M1 Garand was standard issue to US soldiers and marines for most of the war and was probably the best infantry rifle any nation produced.
As another example, the German Panzers V and VI would likely win if matched up one on one against virtually any American tank. But, the Vs and VIs were produced in relatively small numbers and the VIs has some pretty serious reliability issues throughout their service. On the other hand, the most common German tanks (the Panzers III and IV) were not at all superior to the most common American tank (the M4 Sherman).
The author is right that the German 88 was a helluva weapon and was better as an anti-tank and flak gun than any one gun the Allies had. But one great artillery piece doesn't mean that the Germans were better equipped.
I can't speak to all the weaponry listed, but in many cases what was better on paper was not better in the field. The MG42 is a great example. People often say it was the best machine gun in the war because it had a very high rate of fire. And it was indeed terrifying. 25 rounds per second (compared to ~10/sec for the M1919 or BAR), accurate, relatively lightweight, relatively inexpensive and quick to manufacture, and it was engineered so barrels could be swapped out quickly when they overheat. The MG 42 has it all, right?
Well, no. That rate of fire was a serious problem. A squad had to carry more ammunition, along with six spare barrels. The lower weight compared to the American machine guns meant it could be swung to a new target slightly more quickly, but a squad had to lug around a lot more weight to support the weapon.
While it was designed for quick barrel changes, the engineers overlooked one very important factor: the barrels would be scalding hot. There wasn't a cool handle on the barrel to grasp, so you would have to awkwardly flip it open without actually touching the barrel to release without burning yourself.
What about accuracy? Well, heat affects that, too. The first few seconds of fire it proved reasonably accurate, but as the heat builds up the barrel begins to distort and accuracy decreases rapidly. In practice its accuracy was rather poor.
What about manufacturing? Well it was cheap and easy to manufacture, in theory. However, it became immediately apparent that the build quality of the barrels was critical. Each barrel had to clear multiple inspections before it could be put into service, and this practice continued throughout the war. Considering each one required six spares, this wasn't exactly an efficient use of time and manpower.
Do those extra rounds per minute provide any real combat advantage? I honestly can't say, I never served in the military and have never fired a machine gun. Perhaps in some situations (suppressing fire, fear factor, maybe others) the rate of fire was an asset. But in general 1 or 2 bullets will take out an enemy just as well as 5. And stopping to reload/change barrels more frequently is certainly a drawback.