What? your whole argument of why this thread is fail is because GSP is younger? WTF? Randy Couture didnt even step in the cage until he was 35 and by that age GSP will probably be retired, so does that make Randys career worthless? your argument doesnt make any sense.
If the OP is going to use career achievements to discredit GSP, then their ages are completely relevant. For all we know, by 36, GSP might be finishing every opponent he comes across in devastating fashion, just like Silva.
Assuming both fighters began fighting at a similarly young age, I would say what GSP has achieved at 29 is damn impressive.