The reverse can also be said. A newbie in a far superior plane couldn't shoot down a vet in a slower, inferior plane. Verdict: It's the pilot not the plane.
No, the verdict would be
"it's the pilot not the plane", if the superior pilot shot down the neophyte.
In this case, which is the usual case, which is why the vets get mad and angry in the MA in the first place, is the neophyte managed a statistical "stalemtate" and ran away in safety despite all his suckage, who by all means probably would have been shot down if he ever engaged more than 30 seconds.
The fact that the newbie pilot survived in the first place proves the "plane > pilot" theory. And the fact that ch.200 rants are endless, is another very big supporting fact to that theory.
Basically, vets aren't getting enough kills, as opposed to the total number of planes they meet and engage in the MA.
They could get a lot of kills if he just gave up on the K/D and started fighting like a n00b, engaging every duel to the death, except the vets don't want to be snuffed out like a candle in the midst of a horde - they wanna survive, live long, and still get many kills and land in safety - which they can't do in AH2 (due to various changes in the game, the largest being the gunnery).
Since they can't catch the average guys in uber-rides who has some basic SA to at least know when to run away, all they can get is the greenest guys around who presents almost no stimulation in the fun of air combat.
It's like sex - people aren't getting enough of it

, so they're all horny and bitter and jumpy and start ranting on ch200 the moment their foe runs away, and they realize they can't catch him.

Within common sense lies wisdom - people say the "timid flier" phenomenon is plaguing the MA, and people hate it. When you look into it, people can afford to be timid since its rarely likely they'd ever be caught and shot down while flying a P-51 or a D-9 or La-7, as long as they just know when to run away screaming. Ofcourse they're timid - the plane they fly are so fast that they don't need to learn any ACM.
In the end, the plane factor is material, physical, and solid in relative strenghts and weaknesses. The pilot factor is inherent in the human, which cannot be quantified, and varies upon situation.
The first rule of all fight/engagement/battle/war, is to secure a thorough material, physical superiority over the enemy. Same thing applies to air combat.
In the end, as long as you're in the fastest plane available, you'll at least manage a draw

Even if someone else brings the same plane, if you have a head start he'll never catch you.
The only instances where the pilot has to actually have to try and use the "ACM" stuff is when somebody comes in in the same plane, with a big alt advantage so they can catch you.
Voila - the reason why people are timid is given.
In other words, the MA is being plagued by
timid pilots, because the MA works that way and the newbie, sucky, lame, average, who-ever-is-not-an-ace pilots instinctively know that. In the MA,
it's the plane, not the pilot.