The idealised picture of British working class life never existed. It's no more true than theirhmiddle class chocolate box cucumber sandwich, summer picnic idea of Britain. Working class life was hard and miserable, whilst middle class life was just miserable.
The destroyer of community is the changing labour market. People who lived together worked together, socialised together and even worshiped together. They even had the same 2 weeks off work together and probably went to the same seaside town together for those 2 weeks. Consequently they married each other, were (non-familial) 'aunts' and 'uncles' to each other. etc etc. How many people work at the same place as their neighbour these days?
While there is a lot of truth in what you say, the image of most of the community using the pub is not a myth. It was the place to go for the vast majority of people. Not everyone by any means but most.
And while life was hard, it doesn't follow that it was miserable. I grew up in, certainly by today's standards, hard times on a rough council estate. But I mainly have warm memories of it. Not rose tinted ones, ones remembering how hard it was but because pretty much everyone was in the same boat it seemed normal.
Which is quite handy because if I don't find a new job ASAP I could be heading back there!