Ah, the legendary P-39.
From a performance and handling standpoint the P-39 was a tribute to the capabilities of the Bell sales organisation.
Recognizing the desperate need for competitive aircraft, Bell could always be relied upon to miss every performance requirement while citing delivery needs, and to miss every date requirement citing the need to work on performance.
Given adequate engineering support from NACA, Allison and the AF, Bell could have had an improved P-39 as good as any other late ww2 fighter, in front line service, several months before the F-86.
The US was stuck between Lockheed's small production of expensive, complex, difficult-to-use but high-performance aircraft and Curtiss' high production of simple, robust but obsolescent under-performers. They needed something cheap, reliable with competitive performance and Bell was able to give them an aircraft that was expensive, complex, difficult to operate and an under-performer.
Frankly, when it comes to the P-39 the jokes just write themselves. Within the constraints of the USAAFs then doctrine of 'turbo or bust' it was a creditable attempt at rethinking how to build a better interceptor but turned out to be badly flawed in execution, and unfortunately had to be pressed into service for lack of anything better. Once the first panic was over the western allies had far better aircraft to choose from so it went to the USSR who were delighted to supplement their own tactical low-altitude fighters built in tractor factories by farmers with a zero-cost tactical low-altitude fighter built in aviation factories to aviation specs.
It certainly did a lot of good work but it also got people killed who would have survived in better aircraft, and once aircraft like the P-51 were available it was frankly not worth a cup of warm piss.
Should it have been able to handle the Zero? Depends on what is meant. With better training and tactics might the allied P-39 pilots have died slowly enough and bled the Japanese more, enough to make a difference? Quite possibly.
If two identically skilled pilots squared off in P-39 v A6M with no tactical advantages, should the P-39 driver be expected to win the majority of the time? I doubt it very much.
All I'm saying is I prefer the facts to heresay. .
No, you prefer your fanboy obsessions over the experience of the people who actually had dealings with these aircraft in WW2 and everyone who has researched them in the decades since WW2. Just like all the Wehraboos who insist the Germans could have won the war if only they built Napkinwaffe jets in 1941 or got Hugo Boss to make them a sharper-looking uniform.
And there is no such word as heresay. You can have heresy or you can have hearsay, but you cannot combine them into one word. However that is another fact I am sure you will continue to ignore.