But this is a new argument. You said "chess doesn't add pieces". It did. A long time ago, when the game itself was still (effectively) in development.And Civilization also added pieces before. The last change in Chess was en passant and was over 100 years ago, and even then it was just a small change (that had big impact, but a small change)
But when new ways to play the game came, like Freestyle/Fischer random it was adropted as a NEW GAME MODE, it didnt replace the original game. That's the difference
That's what happens in video games (which is also why it's a poor analogy, as others have pointed out). Chess is a historic board game played by numerous people and cultures across the world, some of which evolved into their own offshoots. Civilisation is a video game franchise with entries popping up every several years.
Regardless, Civilisation always replaces / changes / updates the base game mode. It did with 1UPT. It did with Districts. It did with everything older games added that was new to the franchise at the time.
This argument seems to be constantly going round and round this point. The fact that you, this time, do not like the change. That the change was bigger, or unique in some unprecented way (that is different from all the other unprecedented changes). And that's fine. The fact that this time, a lot of people don't like the end result. Again, fine. I'm not arguing that. But the chief conceit in these critical arguments seems to revolve the idea that VII did something objectively bad that no previous Civ game did.
And I'm sorry, but that's such a shallow understanding of what it takes to release a game, and the factors that impact on its success, that it's why we're still going in these circles (everybody, really). Because for some people - certainly for you, and a couple of others - the problem has to be the mechanic(s) you dislike. It can't be anything else. That's why the reasoning is post-hoc. Because you've decided on what is bad, and you're working backwards from that to make everything else fit.