I stated clearly in my post that the fee is insane but it has to be contextualized within the existing inflation in the market.
Well, judging football talent can be extremely subjective so I have no problem with your take on Mbappe. I only shared my own view while I also admitted he may flop or never meet up to expectations like some of the examples you gave. That is a reality of life and not just football.
Most people agree that Mbappe is very special. Scouts, coaches, journalists, pundits etc. That has to count for something. The same hype surrounded players like Messi, Ronaldo, Iniesta, Rooney etc after their first seasons as young lads. There are many other young lads that never get the same level of hypes and that tells you that people tend to recognize special talents. Again, like you said, it doesn't mean that such talents always blossom as much as people expect.
This is where clubs take risks. It was risky when Barcelona paid a world record 5 million pounds for Diego Maradona back then and it was risky when United paid about 12 million for Ronaldo to get him out of Portugal.
It's true that Mbappe has had only one successful full season, but he was observed for a few years before then. Last season only validated the notions experts had on him.
Anyway, the whole situation is interesting. Let's see where things swing.