I have 560 hours in Civ5, 850 hours in Civ6 and 160 hours in Civ7 already. Based on how fun it is to me and the amount of coming content/patches ahead, I expect my Civ7 hours to be much higher than Civ6 in the end.
But to each its own. With radical changes it's totally understandable that some players who like previous versions aren't happy with Civ7.
The challenge for Civ7 will be to attract new gamers, ideally in larger numbers than the ones who pass in order to stick with Civ6 (or earlier). This is what Civ5 did, building the client base even though many long-time Civ fans hated the game and stayed with Civ4. It's what Civ6 did even better than Civ5, broadening the client base significantly, which more than made up for people like me who found it boring and stayed with Civ5 (it also helped that Civ6 brought back some of the fans who skipped Civ5).
I'd have more confidence that Civ7 will ultimately succeed if the launch hadn't gone the way it has. They seem to have found a staggering number of different ways to turn away potential customers:
- new mechanics associated with an unsuccessful competitor (age system = Humankind)
- no England / UK (a huge market) in the base game
- sloppy UI that turned off people who bought the game because they didn't care about the above
- embedded Denuvo DRM code to dissuade some of the people who wouldn't have cared about any of the above
- a DLC shortly after the base game launch that caused some people who wouldn't have cared about any of the above to feel like Firaxis/2K are being greedy/charging too much
- mixed AI quality reviews keeping people who care about that on the sidelines
- no Genghis Khan

("Not including Genghis Khan in the base game was a mistake." - every Civ lead developer)
Now they're facing headwinds associated with a lot of negative reviews, which will make it harder to find new people to try out the series for the first time and harder to attract former customers who hesitated to buy the game on launch for some or all of the reasons above. Can they overcome this? Yes, especially the UI (In Sukritact I trust!) But they have their work cut out for them.