I got my first Android phone, a Moto Droid, in 2010. It's wasn't my first smartphone as that had been a quest with varying degrees of success for years (I still miss the Nokia E series keyboard phones a bit).
Among the things installed on it was Facebook. Even then I was suitably suspicious so wanted to remove it, except I couldn't without rooting as it was a system app, and this was the awful wrapper-around-the-website version. However, being a system app, it still had full access to your phone. Which was nice.
However, by 2010 it had been being installed for a few years, if not as native app, as phone provider bloatware, and I think this was a major contributor to Facebook's takeup. You took your phone out of its box, went through the welcome screens and there it was. You could sign up and you could speak your brains to your heart's content.
I think this was as important a change in Internet culture as Microsoft putting an icon on the Windows 95 desktop labelled 'The Internet'. No, wait, come back.
Large scale social networks were not a new thing when Facebook went global. Friends Reunited created networks based on school connections in the late 90s. Six Degrees, Livejournal, Friendster, Myspace, Orkut all came and went to varying degrees. Google tried and couldn't get it to work, even when betting the farm on it. In that context, Facebook survived and persisted by learning continually, starting with putting the icon on your desktop/phone screen.
It annoys me that I have to keep a Facebook presence, for a few friends and that the parents of my daughter's school use it for messaging, but it and WhatsApp are the lowest common denominators for messaging, but I've handed that off to a bridge - I'm testing Beeper, but could fall back to Matrix bridges (same thing, self hosted) if it doesn't work out.
Of course, this is little compared to having a whole device under your control, especially when Google has now seemingly decided that it doesn't believe in the open Internet any more.
I'm not going to say 'this is what you should do' on this blog at any time, but I am going to say 'this is what I'm going to do'. I've been online for nearly 30 years, nothing compared to some people, and one of the compelling things about the Internet for me is interoperability. Walled gardens always become overgrown, and when someone decides to effectively turn one inside out, then it's time to do some weeding (yes, I'm prone to that sort of hyperbole, sorry).