Third spaces are one part, but honestly the biggest part is literally not having time to spend with people outside of work.
edit: biggest part for me. my friends are mostly able to host at our own houses, and there are low cost (or free) third spaces we have found/created.
if you want a third space, you can actually make your own! kind of. reach out to libraries, local left-leaning businesses, and they might let you set up a weekly salon/hangout kind of thing. community activism!