At a certain point they’re beating a dead horse. Outside of graphical updates (which I thought the cartoon-y look of the leaders in civ 6 was a huge downgrade), the core gameplay is still mostly the same throughout the series.
I watched a video on civ 7 and it seems like they really tried to shake up a lot in the game, I think for this reason that they needed to try something fresh to stay relevant. But really this is to its detriment rather than benefit.
I’m not sure if the three age thing is to “even the playfield” on those marathon long sessions when one civ runs away with the ball so to speak, but really that’s one of my favorite parts of the series. Like it’s awesome to take out some cavemen with navy seals or launch nukes when everyone is cowering in fear. If everything gets massively reset, then why even try to get ahead? I’ve not played the game so there could be more nuance but that’s my general impression.
Usually something hyper specific. This was a few years ago but I found a very bustling community forum for appliance repair. I posted a question on how to fix my oven and got very detailed answers and technical info involving the circuit board and heating element and troubleshooting steps. Unfortunately the general consensus on there is that for a lot of appliances, the board needs replaced which may or may not be available, and if it is, costs damn near what a new appliance does. Which is obviously done on purpose to drive sales.
The other one I know is my friend will participate on one for modding Toyota Yaris cars.
Bodybuilding / fitness forums are still pretty active.
All of these tend to have subreddit or Lemmy equivalents however.