Iron steam i found that it was not the case. The rapid pool is stronger and requires more effort per game to win
Rapid pool is a lot weaker, although around your rating it starts to be about equal.
It's not the players that are stronger, it's the fact that having more time means you can't get away with as many mistakes.
I'd be surprised if a 2200 3+0 player couldn't get to at least 2000 in 10+0 games.
Logically speaking, a 2200 Blitz player should play even stronger in Rapid, since they have more time to think ...
Logically speaking, in 10+0 games the increase in quality due to time will apply equally to your opponent, meaning change in time can't predict rating from one time control to another.