As much as I love Civ 5 still, I haven't gone back to it since I started playing Old World. It's certainly not perfect, and other 4X games do certain aspects better, but it is a ton of fun. Definitely my favorite 4X game right now. Looking way more forward to the new DLC next month than I would have been for Civ 7 if it didn't already sound off to me.We are at the point where another "Cities Skylines" situation can happen in the gaming industry:
A rogue studio with/without publisher backing could make a successor to Civ IV with modern tech - Old World seems to fill the void more than fine for enthusiasts, and Mandalore/Hooded Horse is publishing Endless Legend 2, Age of Wonders 4 is the only good Paradox game in recent memory (while their closer Civ clone Millenium fell to the wayside), so we may see a cultural shift to one of the above paving the way toward the future.
Heaven forbid Firaxis meet the competition head-on, and excel where they have otherwise failed time and time again. Even XCOM is dead in the water, no news on XCOM 3, but Xenonauts seems to be eating its lunch just fine. If they don't get their act together, it's entirely possible Firaxis could be shuttered within the next decade.
I also recently started playing a bit of AoW4 again. Haven't played since like the first DLC, so trying to get all the new shit down, but it's also a fun one. I also still like loading up an Endless Space 2 game every once in a while. Also been wanting to go back and play Endless Legend more. Actually reinstalled it like a week before the EL2 announcement. Last time I tried playing it was back in 2016, and I didn't get too far into it.
As far as Civ 7 goes, like many others have expressed, I'm pretty cautious on it due to some of the questionable design decisions, but I also wasn't a fan of Civ 6 when I tried playing it, so I was always going to be cautious of the next installment because of that. I have no plans of buying it anytime soon, if I end up at all. I don't think there's anything that'll dethrone Civ as the top of 4X games any time soon, but there's definitely plenty of other choices out there that may start steering people away if public opinion of the series starts to go down more.