Like the rest of the World Wide Web, they didn't go away. We did.
We got lured away from the World Wide Web into the shiny and green walled gardens. Now we forgot what's beyond that wall, and we're only just noticing that the garden's flowers are wilted and its grass is long since dead.
The World Wide Web is still there, only diminished by our absence and invisible behind the walls of the worst tech corporations selling us a utopia that isn't.