Ghengis,
I am afraid it isn't whether or not someone has the mental ability or suitability for the job it's the various airlines and operators that expect a suitable age commensurate with experience thing and the huge financial risk that this industry is.
Many flight schools will push the "yep, do our course and you're in the running with BA or other such jet operator" without really explaining what the industry is actually like. You know the variables and the risk but does someone who's 38 with a mortgage, kids in school, good pension etc? If they read this forum then they are made aware that not every one will get the FO slot on an expanding airline flying A319 or B737s with command in only 3-4 years time.
Something else I find frustrating is just how narrow people's expectations are. If it's not a shiny jet then they're not interested. Couldn't care less about charter, piston ops, going to Africa or other such place, corporate etc. There is a lot of aviation out there just waiting for someone to do it, the usual catch is that it often involves moving away from home and the pay isn't as good as a shiny jet job. I guess there's the rub.