As we get better at traveling further for work / school we build relationships with people who are less convenient to maintain.
These relationships demand higher effort than a local relationship and are more fragile than relationships built on convenience (assumption).
IMO the solution to this is to somehow decouple where we work / learn from who we work for / which schools we go to so that local, convenient people can work and learn together on different jobs / courses and build relationships that are convenient to maintain.
Right now i think the neucleus of our social lives and the places we build the most of our relationships (school, work) are too far from the places we relax (home) for us to easily maintain longterm, social relationship because those relationships are often founded and maintined through convenience.
That or we need to spend less time working and officially dedicate much larger portions of our lives to maintaining social lives. We could do this trough reduced working hours, increased leisure time and perhaps some sort of “hanging out” subsidy so that people without disposable income can afford to travel to spend time together.