Quiet, metal boy.

Does anybody who grew up in the nineties remember Spock's Beard being popular?

Nope. TH is living in fantasyland.

Dude, you were like five in the nineties. Not that I'm disputing your point. Just sayin'.

I was a very smart five year old.

Just using them as an example. Just cos you were too busy banging your head doesn't mean they weren't popular. You just hate prog. I can't think of any other big American prog bands at the time. Also, shut up.

Spock's Beard didn't even hit the charts. Maybe they were popular in the wanker niche, but I don't think they had enough reach to be considered "popular".

As far as I know Steven Wilson is pretty damn popular nowadays.
Charts and all.
Are there other examples of popular contemporary prog? Or is it just him and not a genre revival?

I think in the days of grunge, post-grunge, nu metal, and pop punk, prog wasn't exactly in line with the then-current cultural zeitgeist.

Opeth is the only one that really comes to mind, and Wilson's pretty involved with them too.