"Rule" is a strong word, and I dislike this idea that games are thrown in some strange death match. Yes, sometimes games released in same time will fight over community and one will lose, but I doubt when newscomer will come, it will do same things and will be liked by same people in this case.
Also said that to roll out such game is extremely complex and not only takes lot of money, but lot of know how. Despite what your boss might say, not everyone is replaceable.
So rule? No. Everspace, X games, even EvE is still going strong. Each game has it's own community and there's lot of people playing some of them in same time.
If you mean some MMO like, then I don't see it happening any time soon. SC is a bust, and any other newcomer will have to prove it is way better than ED at release to gain any traction.
Who cares? Enjoy what you want from them all.
Also this.
Anxious to see Bethesda's Starfield to be honest, although it might be a completely different type of game than ED.
It is their Mass Effect. So yes, different game.