They are cheap to operate now. This is something governments and big tech will fix.
As I said in another comment they are no longer as cheap to operate in the UK because of regulatory requirements, and this sort of regulation tends to get copied and extended around the world. All for the sake of the children, of course.
How much will it cost with UGC requires age verification and round the clock moderation? When its a risk to do it without a company to shield you from liability?
Local bike clubs and hobby groups presumably know their members, so age verification and moderation aren't issues. Despite computers theoretically being able to connect to anyone in the world, you don't have to use them that way.
Its fine for some groups, but its extra work (you cannot just let people sign up, the admins will have to add each user individually) and for many things you want people to join. A very local hobby group might be OK, but anything broader is a problem. A hobby group for a city? A community forum for a village?
You don't need a centralized approver; you could give any member invite privileges or have a shared password or QR code that members can give out, or that can be shared at in-person meetups, etc. That should work fine still for a city-scale group (which in practice is still going to be maybe a few dozen members). Community forum like for a PTO is also the exact type of thing I had in mind. Print a QR code with embedded password on flyers.
Its still going to create extra costs and risks. What happens if a member over-shares a QR code? What happens if you trust the wrong people? Children can scan flyers too. Governments will move to close loopholes and get ISPs to block sites. Technical solutions do not fix social and political problems.
This is certainly an American perspective, but I wouldn't worry at all about such things. The government has no legitimate interest in regulating your local bicycle club's discussion forum so you should be about as worried as you'd be not going to church if a law were passed saying everyone must be Christian.
Someone is always hungry and willing to ignore international norms for a greenback. Vanuatu will sell citizenship to any hoodwinking criminal for a paltry sum. Comoros will sell internet "gaming licenses" to any money launderer with some change rolling around. Some other shithole island will happily not pass the law so that whatever warlord is in charge can buy enough coconuts for the plebs not to overthrow him, by selling pirate internet services. Then all the forums will be hosted there.
Those thing will be priced to be affordable by the right, not normal people.
Selling pirate services will not solve the problem for someone running something like a community forum for their area, or a national forum for their hobby, or similar. You are still within the reach of your own country.
As I said in another comment they are no longer as cheap to operate in the UK because of regulatory requirements, and this sort of regulation tends to get copied and extended around the world. All for the sake of the children, of course.
How much will it cost with UGC requires age verification and round the clock moderation? When its a risk to do it without a company to shield you from liability?