a lot of things have changed.
We no longer live in the same street for generations, so we no longer have that existing social network to grow into. Many of us have to build it from scratch, multiple times over.
The social culture has changed significantly. Locally, there used to be hatches on every pub. Mum and dad could socialise inside, while all the kids hung about together outside and bought pop and sweets from the hatch. This, and other family-centred social devices, no longer exist. It is no longer socially acceptable to let your kids roam the streets until the streetlights come on, meaning parents have to be On Duty a lot more, even supervising their kids at the park where previous generations would have just waved them off.
Work is now less stable, meaning people end up moving jobs more frequently. This means it's much more difficult for colleagues to become friends. It also often ends up with longer commutes, sapping time and energy.
If they move house for work, it disrupts existing friendships and support networks. Without them, it's far more difficult to share childcare duties, so also more difficult to do other things.
It's far more common now for families to either be single-parent or have both parents in work. This leads to evenings and weekends used up with housework, and less time for socialising.
Housing is also unstable. Fewer people can buy, more are stuck in private rent, and that means having to move often. You can't get to know people in your street if it isn't your street for more than six months.
The gig economy makes predicting work patterns impossible, and therefore planning free time activities is impossible. It also means nobody ever knows when you're available, so dropping round doesn't happen.
Not all of these affect all people. But some selection of them affects enough of us. The old trope of chatting over the garden fence just doesn't work against that backdrop.
