Yes, hit games are still popular enough for sequels (world of goo 2 came out 16 years after the first one, according to wikipedia, which is an unusually long time). I remember World of Goo being one of the few choices of games for iPad when it was young.

But the vast majority of developers aren't lucky enough to have massive hits, and so money differences can still matter.

>comparing unique IP addresses to number sold

Wouldn't that be beyond a flawed system? I would count as a "new unique" player every few weeks.

I think it was a daily scoreboard so that wouldn't be an issue, but they themselves said the number was flawed, just not that wrong.