> One needs to make their server machine accessible to everyone
No not really, what gave you that idea?
> which isn't generally possible due to how networks work
Complete nonsense. Lots of people do it, many more have the capability even if they choose not to use it.
> Also one needs a domain
Nice to have, but completely optional.
> These barriers are high enough, so that common people can't create/host their own sites.
Are you talking about a website? Like a blog? If so you can have a Neocities site for free, with an optional 5 USD monthly subscription. That's the accessible, affordable option you're looking for.