I've literally never heard that view expressed. Can you give us an example of that view being supported?

You can thank a mixture of Rommel Myth style politics that downplayed internal failures in favor of praising the enemy- because rather than admit that you just weren't ready for a bunch of Angry Germans running around in France and north Africa, it's easier to just say, "oh, they're just that good! They're brave, honorable soldiers we're fighting and it's a good clean war! We may be underdogs but doggonit we're gonna win!"- and historically bereft reporting of 'facts.'

The Nazis made for great story telling because where other countries either downplayed or outright stopped work on untested technologies, the Germans were desperate for a cure-all and were willing to go as whole-hog for them as they could manage. So no, while the Germans did mass produce the first jet engine aircraft, it was downplayed by the fact that the British had one in the same time frame, and numerous countries had working concepts of jet aircraft, they just elected to either not use them- the British- or were dissatisfied enough with them that they favored what they knew worked- the US. The ME262 was fast but it wasn't reliable- the guns had the longest life span of any part on the craft, let that sink in for a moment- and had serious issues with regards to acceleration. Even the Soviets were experimenting with the basic concepts of the jet engine, but a few million Angry Germans tend to make you shelf experiments for what you know will work. The Soviets may have lifted jet engine designs in near-whole-cloth from German designs post-war, but the Soviets were dropping their first generation of jet aircraft as soon as possible.

Or rockets. The V-2 really only sounds like a good idea- a strategic scale weapon you can employ from mainland Europe to attack targets in Britain? Sign me up!- but in reality was excessively wasteful. Not only did the V rocket program kill more German slave labor and personnel than it did intended targets, but it was actually more expensive than the Manhatten project.

Night Vision? Yeah, sure, most countries had figured out that you could use IR band lamps to see at night, but only the Germans though it was a great idea to give soldiers and tanks a scope that would let them see at night, and let everyone else see an eerie red light where the enemy was.

Or some aircraft designs that were impractical enough that I assume a bunch of nerds were in charge of the design committee.

Ironically the most enduring German designs were some of the most simple- MG42's, jerrycans for example. But explaining how the Germans figured out that you could build an effective, light, inexpensive machine gun from stamped steel doesn't make for a good story. How Germany 'almost' came up with a nuclear bomb, or how Germany had the 'first' jet engine aircraft or 'wunder' tanks, that makes for a great story if you don't mind being a bit dishonest with the audience.

That, and people like to drag every last example of first hand accounts and 'my grampa' this and 'my father' that. First hand accounts are not a bad thing, but relative to statistical analysis and macro scale views can often tell a completely different story. When you haven't slept properly in a week, got death breathing down your neck, screaming angry Germans trying to shoot you, its fucking cold out, it's snowing, you've been peeing and crapping into your helmet for the last 2 days because you don't want to take a mortar while you're hunched over a tree, and you haven't had a meal that didn't come in a can for 3 weeks, you're probably not in a good mood. Some might say you are, in fact, 'stressed.' Stressed, malnourished, grouchy soldiers are probably not going to give you a good account of how things look on a continental scale, even if their accounts are still interesting. So you get someone like Belton Cooper, who's job was to fix up broken tanks and clean them up- so you know, he was cleaning up people that'd been reduced to ground beef essentially- and his general reaction was, "Wow, a lot of people die in these things." And that gets held up as a macro scale narrative as opposed to an individual account. It makes for a compelling story, relative to dry statistics telling you that American tankers actually had the best survival rates of the war. Or how most German 'super' technology didn't last 5 years post-war, while some of their most unassuming, generic equipment had- have- prolific post-war use.

So, TL;DR, it makes for a good story. Kind of like how your favorite sport team's comeback in the 11th hour to win a game is far more interesting than that game where either nothing really happens, or they just kind of knock the tar out of the other team.