The issue is that few large users or curation groups have any "market position" [RIE81]. (See the references in my Standardized References List.)
Due to the large amount of content, absent any smart recommended algorithm, the expected value of any search within the time/interest/resources budget of the user is most likely to be below the benefit of a typical search. The typical search by sampling will draw a blank.
So users bookmark 1st, 2nd, 3rd, consistent creators and read that, if anything at all.
Daily content of high quality (which is defined subjectively but consistently) is needed for market position to be obtained. But the reward for daily content production is too low, combined with many other issues. For most users, they have nothing to read or write that makes permanent archiving significant. So they remain on the larger platforms, especially when attention spans are low and people seek instant gratification [LOR73]. Yet account creation for their friends, unless they make accounts, takes weeks. Their friends lose interest and don't show. Without their friends, they lose interest and leave ...