Funnily enough, the problem is the same in Europe. In the area around Frankfurt (VATSIM’s busiest airport for the last years), you will rarely if ever see _CTR online if not at least _APP is staffed who in turn will usually want at least _TWR online - and the chain can go on to _DEL (which vice versa results in situations where there’s good staffing but someone at the bottom, e.g. _GND, is leaving and everyone else then has to leave as well due to too much workload). Part of it may be due to the much more densely packed and thus (presumably) more complex airspace, so a reduction in size may still yield a positive result in the US, but in my own experience and from what I hear from other controllers, the problem is often rather a lack of frequency discipline and pilot competency than the actual size of the airspace.
20 pilots on frequency is perfectly workable if they all answer promptly and execute their instructions correctly, but the same airspace can become impossible to handle with just 5-10 pilots if you need to call everyone thrice to even get a response, constantly correct pilots because they are not executing their instructions correctly, and every other pilot tells you their entire life story on each call.
In my opinion, the only real way to improve this situation would be to require more skill from pilots, as dropping topdown entirely often doesn’t reduce the workload that much (pulling pilots from unicom and more often than not fixing their routing, resolving a conflict caused by unicom, figuring out how to descend them in time after they stayed way too high for way too long, etc. is one of the things that actually puts a significant amount of workload on controllers) but that has always been a tricky subject… However, I could also see a system work where vACCs have more power over who may staff which kinds of positions and are allowed to build a system that works well with their specific airspace; particularly seeing as the VATSIM system turns around the amount of controllers at each level compared to IRL - IRL the large majority of all controllers are ACC (and - where that differentiation exists the same way as it does on VATSIM - APP) controllers and there’s only a handful of TWR etc. controllers - VATSIM’s controller training and topdown system on the other hand results in a relatively large number of TWR etc. controllers while ACC-rated controllers are often far and few between. I’ve talked about that last point a bit more in this thread.
And this is how things will still work for the remainder of this month. After that, GCAP will come into effect and - at least technically - prohibit dropping topdown service (unless you are staffing a position that is specifically defined as not providing topdown service and have approval from your (sub-)division to open it without another station providing that topdown service being online). I guess in the original sense of the post, this can even be a good thing as it should force controllers to go offline or switch to another station when the workload is too high, but in practice controllers will most likely stay online and either try to still work the position or just disregard the policy and drop topdown service anyway.