If you play a single game of Civ 7 with a standard Continents+ map and standard settings, the game design guides you through a relatively standardized experience. You'll compete with your neighbors for good settling spaces in the antiquity, then leave the old world behind to explore and exploit a new world in the exploration age, and finally choose and pursue a victory condition in the modern age. There are 10 to 20 hours of solid fun to be had in such a game, despite some obvious shortcomings in matters of bugs, user interface, and balance.

But the more fundamental problem is that Civilization as a series isn't about playing the game once. Civ 6 was a game that managed to consistently have between 50k and 100k concurrent players for over 8 years on Steam, up from 30k players 6 months after release. Civilization is not only the "one more turn" game, it is the "one more game" game. But right now, Civ 7 isn't providing a lot of that. If you play a second or third game of Civ 7, you'll feel a bit railroaded into the same experience as your first game. If you experiment with the game settings and try to play in a very different way, you feel as if the non-standard options are somewhat unbalanced and half-baked. And if you try to play in "house rule" / challenge mode, setting yourself limits against exploiting some of those imbalances, you'll feel as if the game is punishing you harshly on several levels, but especially on the meta-progression level.

What is especially annoying for replayability is how brutal Civ 7 sometimes is in twisting your arm to play the game in a standard way. Civilization VII has only 3 ages, compared to Millennia's 10. But Millennia basically lets you keep everything from one age to the next, and just changes the rules for the next age. Civ 7 goes through a very harsh reset on changing ages, totally nerfing your current buildings, and reshuffling or even deleting your current units, while replacing them with new ones. After you have become familiar with how exactly age changes work in Civ 7, the last 20% or so of an age become a weird exercise of avoiding things that don't carry over, while concentrating on a narrow set of age "victory conditions" and things that do carry over. If you keep crises turned on the settings, you'll also never know what is going to hit you, as specific crises can hurt enormously if you have pursued a certain play style, while other crises are rather harmless in the same conditions.

Sid Meier is famous for having said that a good game is a series of interesting decisions. Of the whole series of Civilization games, Civ 7 is deviating the most from providing interesting decisions. Decisions are interesting if they are all viable. Civ 7 frequently offers you to either play in a rather standardized optimal way, or to deliberately choose suboptimal decisions, which are thus a lot less interesting. A decision becomes less interesting if you feel that the game is punishing you strongly for taking that decision. Sometimes Civ 7 doesn't even give you a choice, which I feel most strongly when creating maps. More often it is things like your selection of enemies in the exploration age: The civilizations on the old continent do not give you any military progress, while all the age progress and meta-progression in military is linked to fighting the civilizations in the new world. That doesn't really feel as if you had a choice at all.

It seems as if Civilization VII was designed to appeal to a larger group of customers, but that some of the fundamental design decisions when going that way limit the lifespan of the game. It remains interesting for the typical lifetime of a typical console game. But I don't see the upward curve of player numbers from the initial dip a few months after release to 8 years later being possible in this iteration. And even a bunch of patches and DLCs aren't going to help all that much there.