Space games in general have had a huge revival, not just sims.
It's great because I love everything about space, doesn't matter if it's games, TV, books, movies, real life amateur astronomy, I love it all.
Another game I haven't seen mentioned is Limit Theory which should be out soon(tm), basically it'll satisfy the niche of what the X series did, if you loved the X series I think Limit Theory is going to be the only game for a long time that'll fill a similar role until Egosoft pulls itself together and makes a new X game that forgets that Rebirth ever happened.
E

is moving forward nicely, it released a little early in terms of features but we got 2 important updates recently and the 1.3 is going to be revealed soon + there is going to be expansions. It has everything you'd expect from the Elite games if you ever played them, it took the basic formula, improved it and added some features, but it's still missing some things that is coming over time already. It has the best combat/flight mechanics of a space game I've ever played, a lot of refinement/iteration went into that to nail it just right. It's a game where there's no other way than up, absolutely stunning core design, now it just needs to be expanded to infinity, which is their plan since it's Frontier's flagship title.
I've been playing EVE since 2005 still, it's just trucking along and getting significantly better with each update, absolutely stunning game if you'd ever take the plunge, it requires dedication like no other game if you play the meta, get into a good social corp/alliance, take part int he meta, have a fucking blast. No other game like it and don't go into it thinking it's like another MMORPG. Fantastic if you enjoy deep mechanics, it has more mechanics at play when in combat than any other game I can think of honestly.