that becomes wildly popular extremely quickly

That's not going to make you $1b. Maybe tens of millions, but not billions.

I guess you could sort-of argue that it's what happened with Minecraft, though that took more than 5 years from the alpha to the eventual acquisition. But, it's true that he went from typical middle class type wealth to a billionaire overnight when that deal closed.

But, in almost every other case someone's going to make far less than $1b on their first deal. And then they're going to be multi-millionaires who either start giving their money away, or try for $1b.