Do you mean celebrities that become poker players or poker players that become celebrities because of their poker play? I don't think "bad" poker play has anything to do with it. I think more US players are playing outside the US. And because of the resrticted use of poker sites now in the US, you don't see all those commercials for sites with all those stars all over the place.
Also a lot of the top players are still wining multiple tourneys. Phil Hellmuth is the biggest example.