I don't exclude those professions but actors chose to mimic others which seems an odd thing for a great thinker to do, astronauts are admirable in almost every way but I don't think they're the greatest thinkers and politicians are just politicians. I'm not sure why I'm defending my position though as you don't seem to have any either
Oddly your list of great thinkers is very similar to my own. Perhaps there really aren't that many great thinkers out there to chose from? I'll admit I didn't have quite so many from Google or any chess players. Oddly none on the list are particularly young.
My suspicion is that people aren't getting smarter. There was a film called
Idiocracy which explained why - it's a fairly low brow comedy but it seemed to have it's finger on the pulse (well worth watching if you worry about your fellow man).