Same games on different sites?

Question

Game development

I looked at websites and saw that many of the same casino slot machines, why is that?

Answer 1

Because one engine and in general many such resources under one owner

Answer 2

Most likely, these are the same successful assets in the store of the corresponding engine. That is, different games buy the same asset slot machine.
Show the slot machine, and it will be possible to say more precisely why this is so.