Kingpatzer, here's a huge problem, your argument goes beyond chess. You are essentially claiming that past 25, it is impossible for someone to develop a mastery of skills in any domain that requires hard work and a high level of learning.
If we can't bring up a specific 2000+ player who started after the age of 25, I'm sure we can find examples of age 25+ adults who have become excellent at some other craft. People begin new things past the age of 25+ and become excellent at them, all the time. Chess is just another skill, like anything else. Your model of the brain (and "Science's" model of the brain) is just not good enough. Your view is certainly not proven, and if it is indeed not proven, why would anyone adopt the belief that they can't do it, and put limits on themself?? (Or why should we place those limits on others?)
... I think it's just some elitistic ideological statements from titled players who wants to show that they are very exceptional so "don't even think about getting close to us you patzers". That's how this impossiblity myth is created. So I don't think that saying "impossible is possible" is overtly sophomoric.
For the record, chess is an elitist sport. Chess rewards the player who can see more deeply and clearly, and those who can remove all distractions to focus on the game.
I'm not saying it is impossible to reach +2000 as an adult starting out. I'm saying that if you accomplish this feat, you have done something truly remarkable and extraordinary. You will have shown that you are far from "average".