Didn't the allies win ww2 almost by luck?

No. They won through overwhelming industrial strength, greater manpower, a superior scientific establishment which was better employed towards winning the war, and the persistence and determination to keep going even when things looked bad, e.g., when Britain refused to make peace with Germany after the fall of France, the Soviet non-collapse (politically) in Barbarossa, and China continuing to fight after the fall of Shanghai and Nanjing, and after the Ichi-Go offensive. And the occasional wise choice.

The combination of those factors led to victory. Absent any of them, and victory might not have been theirs. For example, without the capability to build merchant ships at an unprecedented rate, and the scientific and engineering capability to develop and deploy a range of anti-submarine measures, the Battle of the Atlantic could have gone the other way, leading to British withdrawal from the war. Both the Soviet and Chinese political leadership could have collapsed and their countries withdrawn from the war. Without US and British engineering and science, and the industrial power to produce aircraft in sufficient numbers, the Luftwaffe might not have been destroyed. Etc. Stupidity, suitably applied, could have led to Allied failure.

Of course, lack of Allied victory would not necessarily have allowed German and Japanese conquest of the Allies (unless one could wish away industry and manpower) - the outcome might have been a wary negotiated peace, with the Axis powers holding their wartime gains, and everybody preparing for WW3 (perhaps as soon as the Allies had a sufficient large stockpile of atomic bombs).

Aren't they considered lucky that the Germans didn't have enough time to devolpe more wunderwaffe and things like the me 262?

Germany having more or less time to develop Wunderwaffen wasn't a matter of luck. The time limits were set by the German leadership realising that it was unlikely, if not impossible, for them to win by continuing along conventional lines, and conquest of Germany by the Soviets from the east and the Western Allies from the west. If, in some what-if scenario, the war in the West had continued longer, there would have still been the atomic destruction of any remaining German cities by the end of 1945.

Yes, more time and development would have helped some of the programs reach a usable stage, but given the lack of real impact by some weapons of which development had begun before the war (e.g., the Me262 and Fritz X), the Wunderwaffen that began development mid-war were simply not going to have enough time.

By the time the Wunderwaffen that appeared on the battlefield did so, it was too little, too late. For example, Fritz X was successfully used, hitting a number of battleships in the Mediterranean and sinking some and putting some out of action for many months. Was Fritz X able to stop the Normandy landings? Clearly no (and Warspite, which had spent months under repair after being hit and near-missed by Fritz X, was back in action for Normandy).

Further reading:

Richard Overy, Why the Allies Won, Norton, 1996.