There are no good reasons I couldn't host my own files, with my own bandwidth, on my perfectly cromulant server/mobile device.
The only issue is, it hasn't been considered of any importance to maintain user agency; better we steal the users agency over their data/computers, put it out 'in the cloud', and get them addicted/dependent on third parties, than to make the operating system deliver similar levels of service, at scale, at the local level.
What if, instead of getting all hot and bothered about browsers, OS-teams instead focused on making source-/locality-/ownership- of user-generated data, within the context of the local machine, available at scale?
Like, gimme IPFS open and operating by default, in my regular distro, and I'll never have to host a site on a cloud server again...
Todays computers/bandwidth/connectivity can handle the load.
My systems can certainly handle the load I would impose upon them by sharing content to my personal social network.
What they can't handle is the load imposed on them by the farming of data by third-parties from my feed. But thats okay - because thats exactly what I want to get rid of.
If it was a feature of the operating system, who would host the files?