the open internet is dying. What used to be blogs and forums now is Reddit.

How "open" were those blogs and forums, though in a functional sense?

Instead of an untrustworthy/unreliable corporation like Twitter or Reddit owning a data and community.... we used to have a zillion untrustworthy/unreliable individual "webmasters" owning those blogs and forums. "Your" "community" might be gone in the blink of an eye because the guy running it threw a hissy fit, or forgot to pay his hosting bill.

All other things being equal, the current near-monoculture does suck worse. But the old days sort of sucked too.