I'll admit that I haven't played much of PC as of late (I dabbled with starting a few parks right after the summer update but quickly lost interest). That said, there are two sides of this issue.
There is indeed a fundamental schism between Planet Coaster's identity as a park simulator and its identity as a user-created content game, as the ridiculously enormous (to the point of actually becoming counter-productive) Steam Workshop certainly testifies. There are lots of incredibly talented creators who've practically made PC their own cottage industry via YouTube and the like, and the sheer number of amazing stuff to subscribe to (without mentioning the ocean of mediocrity to wade through there as well) is simply overwhelming. Even with only a handful of themes available thus far (Caribbean/Pirate, Sci-Fi, Western, Snow, etc,) that part of the game has become an oversized buffet for those who love that aspect of it.
The majority of complaints that I've read here involve folks who feel that the park sim aspect of PC has long since been left in the dust, if not outright ignored by the development team (which I think is unfair; they have been making incremental improvements here and there, some of them in direct response to user requests). These are the users who thought PC would focus more on the building and maintenance aspects of the parks themselves, something that the RCT series managed to accomplish before this thing called online functionality (and therefore shared content) became so dominant.
Me personally, I'm not skilled enough at the creation aspect to make anything special, but I've subscribed to a ton of great stuff at the Workshop to help populate my parks. I'm fine with simply planning out, building, and enjoying a park, riding the rides and walking around enjoying it from a Peep's POV. The main reason I haven't touched PC in months is simply that I'm waiting on more themes and their associated rides, décor, animatronics, etc., such as Spooky, Prehistoric, Safari, and Water Park. Right now I just feel a sense of incompleteness with what I have to work with from a thematic standpoint, the plethora of user-created content notwithstanding.
I don't have unrealistic expectations, but I do believe the development team will get to most if not all of these when they can; this is a HUGE game already from a mechanical context, and it takes time to implement big changes in a way that doesn't screw up what's already there. So bottom line, I'm not "angry" or frustrated, I'm just simply waiting for the next major update to see what's coming. The perceived "silence" here recently is, in most cases, probably due to most users doing the same thing. Sometimes there are simply lulls between updates where there isn't much to discuss; it happens and it's okay.
Please don't be so hard on the folks at Frontier. If anyone has actually left the forums, it could well be due to the duplicity often on display here. These guys get praised to the heavens whenever they release one of their surprise (and typically free) updates, but a day or two later you'll read comments here saying the team "doesn't care". That sort of ingratitude poisons the well here and you know it has to suck the joy out of what they do to try and make PC the best it can be every day. They can't tackle every single aspect of such a huge project at the same time; some things will take longer than others, and sometimes what's "fixed" won't be the thing you were hoping for. But with time, I believe they'll get to it. Show a little faith, be considerate in your comments and requests and tactful in your criticisms, and remember that a word of encouragement now and then can't hurt.