While I am always in favour of Discourse being as simple to install as possible, the primary problem is not on the supply side, but the demand side.
I could spin up 200 Discourse instances overnight on range of different interest, but no one would ever use them because of limited discoverability and minimal general demand.
Building a viable community feels like fighting against entropy. If you don’t pour a humongous amount of personal resources into keeping the place maintained and engaging, people will just go to Reddit/Facebook/Instagram/YouTube/TikTok that are highly engaging by default. When I go to public events in my hobby, the default question people ask is “what’s your insta?” because that’s the default window the hobby is viewed through unfortunately.
I like Discourse/forums because the level of engagement is so much deeper. I’ve seen the equivalent of a “Topic” in an instagram story and it’s a joke in comparison. But the barrier to entry to move from instagram to that deeper level is something few cross, either out of ignorance or satisfaction a surface level interest that is satisfied by a social media site alone. In a way it’s a perfect filter to keep out low-value members, but simultaneously it keeps the community generally insular.
So while it’s not something easy to do, the #1 place to shift the current paradigm as I see it is to reduce the instagram/Facebook/reddit → Discourse barrier. How? No idea. Maybe improved SEO or better hooking new users that stumble upon a Topic from a google search.
A healthy balance is like 1 sysadmin user to 100-10,000 users. Making it easier for the one sysadmin users is far less a priority compared to making it more likely that 1000 people to register and use the platform.