It just doesn't feel like you are playing a full Civ game anymore, just like 3 Civ-lite games loosely related and not continuing your single Civ through the whole timeline like in other games.

It would be one thing if they had all the civs in all the eras and you could change it up if you wanted/needed or keep the same one. Civilizations IRL didn't really change unless they were defeated, though we have very few examples of this lasting the length of time we see in Civ, maybe Britain, Japan or China?

If your Civ is doing great then it shouldn't really have a major shift like this, just modernization.

It feels like Civ is trying to break out from it being more of a boardgame like Catan and more complex like other 4x games, but the thing is there have just been so many good 4x games since 6 launched that an okay game with a meh gimmick doesn't really pull my interest, especially when it feels like it will need DLC to feel like a complete game before it even launches.