This was not uniformly accepted behaviour. Yes, some people could find roles and a situation where this was possible before, but most couldn't. Stores didn't really optimize for a self-check out experience.
The social pressure in many organizations and communities to conform was high and there was no escape. If you you wanted to work at a tech company or startup you would have to accept open offices, happy hours, and other social requires to a great extent. It was not acceptable to skip many events and you had no option to switch your working environment in the office because the only option was open space.
The pandemic has forced a change, most importantly, in a relatively uniform manner. I'm not making the argument that we should all accept this other extreme. Just as we return to normality we should consider the experiences of others, and try to make some reasonable adaptations.
Now almost all the aisles are self-checkout and are friendlier to larger cart-fulls like I buy (having a few kids means there's no such thing as a quick trip with a hand basket anymore...).
No one is forcing you to pretend interest in small talk. If you're not interested in it, say so instead of pretending.
Are you afraid you'll lose your job over being antisocial or rude if you don't pretend to get along with your coworkers?
You might be happier if you look for a job you don't hate.
(Also if you stop seeing other people as beneath you, but that's a taller order)
> just go home straight after work
In your own hypothetical example, I'm still required to be in an office or else be jobless. Finding remote jobs isn't trivial.
But what stopped you from distancing from people and using self-checkouts before the pandemic? If you hate people, fine, just go home straight after work, you aren't obligated to hang out with anyone. It is not like the government would fine you for coming home before 11pm, right?