Carlsen will have to hit 2950 before he achieves the same rating gap Fischer had.
Yes, but at the same time Topalov had a much bigger rating gap than Kramnik and Anand ever had taken together. Doesn't have to mean that Topalov is the most talented of the three. But talent is impossible to measure. I've read Carlsen claim that there are periods during which he doesn't think about chess at all, and Kasparov considered him lazy. Carlsen should rank somewhere up there among the most talented players, he is after all only 22 and has achieved a lot (and that without the same level of dedication as many other players).
Definitely, I agree.
I don't know who is the most talented. As you said it's impossible to know. But I think Fischer should be mentioned in the list.
Fact is i personally believe Fischer and Kasparov both would be extremly successful no matter what profession they would have chosen.