I think some of it is just you, and you're right to an extent. Normal users will tolerate a lot of annoyances, including hostile approaches, unfortunately. Pinterest, Facebook, Twitter, Reddit, Imgur, LinkedIn have all repeatedly demonstrated that versus their very large user bases. These are not shrinking networks. Instagram's new cut-off on non-logged in viewing is hostile, it won't dent them at all though. These networks know their users will largely tolerate it, because what they're using doesn't cost them actual dollars.

I think the most interesting story in social networks is the collapse of core Facebook as the prime mover. I think there is still a lot of room for more Pinterests and Snapchats yet, which could further diversify the space and dilute core Facebook's mind share. The young people not caring about Facebook thing, has clearly graduated to a permanent setting, it's not going back (the next group are not going to suddenly care about FB). TikTok has demonstrated some of what is possible most recently.