I get your point here, but even if a person goes against these norms, they still struggle to find other people to interact with. The problem isn't just digital either, the way we build our society impacts this as well. For example, you are far less likely to have a conversation with a car next to you in traffic than someone next to you on the sidewalk or on public transit.

I would say there are a lot of factors. Lack of: money, energy/health, transportation/infrastructure, destinations, time etc.

Anecdotal, but I live in a very small town/village in the US, I'm close to a trail so I got a (weak/cheap+has gears) eBike and I didn't even have it for 4 months before the trail closed for renovations... and 6 months later it still is so I haven't left the house since then. Granted it was more of an activity/utility thing but it was still good mentally and I was still getting into it.

Also see something like Bowling Alone, you probably aren't going to be very social even at a sit-down restaurant as most people probably don't see it as a social thing (aside from maybe the main counter at a bar/diner and even that is subject to unreliable factors).

This is a simplistic view of the problem without consideration for introvert vs extrovert. Not everyone is able to open up to others as easily. Even though the Internet ceased to exist, this doesn't make it any easier for the introverts.