EgoSpengler, The one thing I like about planetbase, is that once you get to that "easy enough to build a sustainable colony" stage, there are still 2 other planets to master, as well as a bunch of achievements. But you're right, it's a bit disappointing that there wasn't a "next gear" you could turn to, after reaching sufficiency. I feel that's one of the things the early Anno games got right, or at least.. uhm.. Anno.. 1404 or 1503 or something like that. But then those games had a problem that you'd set up an elaborate micromanaged chain of supply and demand, and if pirates messed up one part of it somewhere, it could often lead to huge problems. But I mean, even with that, I loved that there was more to do after you became sustainable enough.
The reason I haven't played much of Cities Skylines is.. well, it'll sound silly, but all the mods. I'm a lazy gamer, I don't keep up with which mods are good and which aren't, which ones you need to have, etc. I have been waiting for them to integrate some public transit functionality that was in the transit++ (Or whatever) mod, but.. It seems they're not doing it. Right now my game has a bunch of mods in it, and I haven't launched it in half a year. I don't want to sit there and figure out which mods I should get to make gameplay the way I want it. I want them to make the vanilla version of the game to have all the functionality you need, such as changing transit line colours automatically or whatever. Yeah, I had a lot of fun with the game initially, but can't be bothered to screw around with the mods to make my gaming experience worthwhile.