And the fact that the 51 was fast, performed great at alt, had long range, good roll and good guns, control at high speeds, etc.
It was a good plane. That the Luftwaffe was outnumbered , that was a product of production, it was also a product of that whole 'getting shot down' thing.
No dispute that the P51 was a good plane, although 190s are competitive in many of these areas. 109s less so. The P51D was a good plane, but I'd hardly call it "the plane that won the war". The Brits will claim the Spit won the war... and then there's the Hurri, P47, P38, Tempest, Typhoon... it goes on and on. It's pretty fallacious to claim the P51 deserves a 5.0 ENY based on what you imagine its reputation during WWII was like.
I'd put the following factors FAR ahead of the Mustang's (or really any plane's) performance in terms of Allied air dominance over Europe especially towards the end of the war:
1) Numbers. Consider that Germany was fighting on three fronts at about half the population of the United States alone (not to mention Russia and Britain). In a war of attrition (which WWII most certainly was), you will LOSE that fight, even with superior aircraft. There's absolutely no way around this fact.
2) Average pilot combat experience - with heavy losses in experienced aircrew and no combat rotations, the average level of German pilots deteriorated greatly towards the late war. What good is an aircraft without a pilot who knows how to push it?
Consider also that Germany developed the first operational jet fighter (which was probably far more feared than the P51) and it should be pretty obvious that engineering proficiency was one thing Germany did NOT lag behind the Allies in.