Yeah, give it a shot. And the base game goes on sale a lot, so the buy in could even be really cheap for you.

Keep in mind that ESO is by Zenimax, not Bethesda Game studios, so not the same people who would have been working on TES6. Also, while you may not be one of them (or maybe you are, I don't know you) there was in fact a large demand for an online multiplayer version.

Point being, ESO was made for a certain audience, and as far as I know, it's existence is completely independent from TES6, meaning we wouldn't get TES6 any sooner even if ESO wasn't a thing.

Zenimax is Bethesda, Bethesda is Zenimax. But about the people actually working on it, idk maybe you are right.
As for the multiplayer version, people were asking for co-op style or "small rooms sessions" kind of multiplayer IN the single player game itself. Even back in 2012, i remember playing one of the first skyrim multiplayer mods.

My problem is that the quests and characters made in ESO are wasted there for the people who will only play the single player games. They are not supposed to reuse those quests in newer games.