That's true up to a point. But I do think the average quality of "published" writing has gone down as the barriers to entry have - really how could it not? For every story that a gatekeeper would've rejected because they couldn't understand its brilliance within its niche, there must be tens or hundreds that said gatekeeper would've rejected simply for being bad.
Maybe that's not so bad: in the past you were either famous or not. Now I think we get these common interest communities that all read the same blogs / follow the same people on twitter and great art proliferates in those niches. Maybe it doesn't enter the total public consciousness; maybe it doesn't have to.