The one thing I am worried about the most is the possibility that the team of Forge will just stop, and there goes the end of forge for newer Minecraft editions.

Question is, would that ever be a possibility? What would you do if the team of forge all of a sudden abandons Forge?

No, not in the near future.
Lex is working on Forge as his full-time job (it's stated in his Patreon) and the project is open-source, meaning that the community of developers contributes a lot to it via PRs and stuff.
Forge has been a thing for a very long time and I doubt it will stop being a thing even if Minecraft itself dies. (Probably won't happen in the near future too because of Microsoft and the large community).
Also, keep in mind that Forge is one of the first (if not the first) modding API for MC and is still, to this day, the biggest one.

As stated in our last stream.
There are mechanics in place to protect us from the 'hit by a bus' syndrom.
We don't have just one or two people working on things. I've been working as best I can to make everything in our process open source and teach everyone who is competant how to do what I do.
On top of that, no I don't have any intention of stopping. 
So it's not something i'm too worried about.