Been watching too much History Channel?
The problem wasn't with German Industry making competitive, or superior aircraft. The problem lay in manning the fighter planes with experienced pilots. So not only didn't the Luftwaffe have the training machinery in place to keep qualified sticks in the air , they also didn't have the gas to adequately train them even if they did. But as for German aircraft designers and manufacturer's?? They did a remarkable job keeping very competitive aircraft available almost until the bitter end. Especially considering the huge bombing campaign on the German aircraft Industry. Both factories, component factories, and the fuel pipeline.
The Mustang was a remarkable airplane in that, like the P-47, it could fly so far, so fast, and so high. It could penetrate deep into German airspace and whittle the Luftwaffe down with attrition. The Pilots we trained in them had hundreds of hours of practice before combat while coming out of a training infrastructure that had almost no limitations.
But the attributes that made it so effective in actual war dont necessarily reflect in a computer game. As an escort fighter, a B&Z'er, and even a bomb trucker, I think the Mustang is effective. I have had an awful lot of fun flying it, even if I dont fly it much. Last week against a high ALT bomber mission I met another stang at 30,000' on totally equal terms. The long, long, long dogfight I had with the other Pony, almost to the deck, was probably the most fun Ive had in the game since I joined. I mean my hands were shaking after, know the feeling?
Be that as it may I couldn't imagine a worse plane to be on the deck with, against a K-4, then in a Mustang. Especially since the chances of a noob being in the K-4 are about zero. I'd much rather be in a corsair or a Hellcat in that predicament. Even a P-38. The truth is the K-4 is a very dangerous aircraft. Ive had hard times against them even when in a LA-7.
The guys who are good in Mustangs force you to play "their" game. When you have 2 good sticks flying as a team a pair of ponies can cause a lot of disruption at an airbase.