considering these guys made the humble bundle in between bouts of making this game... (plus a bunch of other projects I personally love)
it's weirdly common for successful game studios to have also been involved in a store of some sort - valve's steam came from trying to sell online, cdprojekt's witcher and GOG, epic's fortnite success -> epic store.
when game devs break out of games they can leave quite a mark. the glitch folks -> slack. or discord.
I would imagine it's actually more likely that a game being successful is such a lottery that they cannot replicate subsequent successes, where as using the profits from previous success to venture out into a different but profitable domain is more, well , profitable.