FWIW, my friend recently built a summer home. I went over about four weekends to help drywall, put in flooring, build stud walls, etc. He's had other friends over other weekends. Sometimes it's just one friend, sometimes a few of us go up together. It's a great time, and definitely strengthens our social bonds.
I'm also friends with my kids' parents (one of whom is the one with the house). Playdates turn into dinner invites.
I think we're lucky that we're on the older end -- mid-40s -- so maybe we had time to work our social muscles before social media and Netflix, and have socialization as an expectation.
I'm also personally lucky I have a wife who does a lot of the social reaching-out. For whatever reason, this seems like it's more and more a gendered role, and I'm definitely worse at it -- if I were a bachelor I'd probably be happy staying home alone much more, to my long-term detriment.