lets be serious here and extremely simple and short for the benefit of those who do not understand the in depth aspects etc.
Any fighter could of flown to berlin escorting the B17's. All they needed were drop tanks. BUT.. Why should the RAF use spitfires to escort american bombers in daylight all the way into germany? what would the american fighters be doing? they wanted to bomb in the day so they can escort them. It worked well between the UK and the US during WW2, relations were good. US fighters escort long distance, spitfires will RV sometimes mid way when they are coming home.
P51 - escort
Spitfire - fighter sweep/recon
i know both the above did more, but im keeping it simple. Basically....why change something that worked? if it isnt broke then dont fix it. Hence why the P51 did most of the escorts.
No denying the P51 is an icon. To the americans its what the spitfire is to the UK. the P51 is an incredible plane, it had a job escorting the bomber and it did it well, dogfighting and gunning down anything that got in its way.
in real life, its amazing. In this game suck terribly. Simple
the patch will sort it though dont worry