I think it is because the "famous" places are occupied by those whose only focus is "becoming famous".
If you are extremely talented and gifted, your focus will be on doing a good work, being true to your call, etc... If fame comes out of it (if other people notice "hey, this is good!"), then it is like a bonus.
But those who -talented or not, doesn't matter- wake up every morning thinking "I'm going to be famous and rich and people is going to drool in my presence and press is going to be following me everywhere..." That's a different goal and requires a different set of skills.
For example, you see a certain kind of celebrities who first tried to "make it" as models, and then it didn't work so they tried as actors, and then it didn't work so maybe moved to singing or TV... In contrast, can you imagine Picasso having a few rough years and saying "to hell with this painting thing, I'm going to try if singing does it?" For people who want to develop their talents, fame is second-rate important or not important.