if you wanted better advice you should have provided more background, 'californiaguy' may not have been politically correct but that does not detract from the fact that he spent some time answering you.
If you have finished or built things academically or professionally you could point to them, which would give a more solid base for this whole discussion.
You are asking for inference, some of that inference is going to be on the spot, some of it will be wildly off the mark, if you supply more information you can guide the bandwidth of the results you will receive.
The last line of his post pretty clearly indicates that he realizes that he may be off in his estimate because he feels like coming across as an asshole. (I won't debate that point...).
Advice - any advice - is worth what you paid for it.
I never once stated that I was disappointed with my accomplishments (whatever they may be), only that I wished to retain (or increase) the level of mental acuity that I have manged to gain so far. For you to derive anything from a conclusion that you have arrived at based on your own personal inference is misguided, at best.
Moreover, the ad hominem attack about me thinking I 'was some kind of superstar and now [..] past [his] prime' is uncalled for, and not necessary to prove your point.
Nonetheless, I appreciate the advice, heavy-handed and flawed though it may seem.