In Markus's defense, I think he added the "stats cause talent changes" in part because a bunch of public board posters suggested this was a great idea. Responding to users is one of Markus's greatest strengths. But this is, unfortunately, what you can get when you listen rabidly to users.
Beyond pure logic, it takes very little effort to gather data that indicates how flawed the idea of stats causing talent changes is:
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I created the following list in 5 minutes of clicking around on BB-ref. I timed it on purpose--that 5 minutes is a real number. Give me 5 more minutes and I would guess I'll double the size of the list.
Mike Schmidt
Sammy Sosa
Rickey Henderson
Reggie Jackson
Craig Biggio
Harmon Killebrew
Roberto Clemente
Pete Rose
Mo Vaughn
All these players struggled in younger years, putting up sub 100 OPS+ numbers (some for several years) without having any issue with retaining their raw ability.
In fact, it is a better logical argument to say that THE FACT THAT THEY HAD GREAT ABILITY IS WHY THEY WERE ALLOWED TO POST SUCH CRAPPY NUMBERS TO BEGIN WITH. Willie Mays was 0-22 upon his debut in the majors. No talent hit there I guess. Barry Bonds almost qualified for the list with his .223 rookie batting average, but managed to slug just enough to register a 103 OPS.
I have seen no argument that successfully shows poor stats, all by themselves, lead to future poor performance. It is ill-logical to suggest such a model is "true" even though it can be made to work in a software environment.