I think it would be worth a try. Make some sort of “framework” theme and then monetize the community that forms around them. The challenge is making it distinct in some way. What would you freemium product do that Astra and OceanWP don’t? I don’t have a good answer to that part.
The core goal of it should be flexible and efficient way to make websites. After being in the theme business for many years, I’ve become increasingly convinced that most people don’t ever really want to “buy a theme.” They want to buy a complete website solution that furthers their goals in life and business.
A big component of this can be the theme. It could also be more of an end-to-end solution like WordPress.com, although if you’re a solo business owner, focusing on a particular industry/goal might be a bit easier to manage and stand out.
There’s some school of thought that goes like A Product for Everybody is a Product for Nobody. This kind of flies in the face of these “all in one” themes that seem to try to be a product for everybody. That’s not to say an “all in one” theme can’t be financially successful. Look at the top earners on ThemeForest, for examples.
Just something to consider.
Nobody can force you to spend time on free version support. Part of your business model could be charging for support. It’s tricky though because without some level of free support, it might be difficult to gain traction.
Also, your paid support plans could be in competition with random Facebook groups (such as the ones you pointed out) you have no control over. You can’t stop people from organizing and discussing your product and helping each other out for free.
Again, just some random thoughts to consider. Hope it helps in some way.