Well, the simple answer is yes, you’re right. And it would!
The not so simple answer is… Well, this has been considered many times before, and the issue is that… well, engines are not like clothes, that you can remove one and put on another and it will be fine. Stonehearth has its own engine which means that the game and the engine are deeply entangled as a single thing. In shorter terms, to have Stonehearth in another engine basically requires you to rewrite/remake the entire game, from scratch, on another engine. So unfortunately it’s not something simple that we just need to swap some files and it would work… 
And that’s only approaching the technical level - there are also legal matters at hand. We don’t have access to the source code of the game, which means that remaking it from scratch is even more difficult - and we don’t have the rights over the game, so even if we did all that, Riot Games could approach us with a “Cease & Desist” order and that would be it 
So we have what we have, and our goal is to try to do the best out of that 
We don’t know what the future reserves, or if someday someone will try to make a game inspired by Stonehearth or anything like that… who knows?
We can dream tho!