Religion / ecclesiastical institutes also served that purpose. There's many meetup tools, really no reason to still depend on pubs anymore. If you need alcohol as social lubricant, take a few shots, bring a (discreet) flask.

I know there's other aspects to bar culture that's more conducive to forming relationships for some people, but I also think the reason why "local" pub culture is dying is because people finally have alternative options, though no doubt many of those options are solitary activities. Though I'm not convinced loneliness is bad in itself, or social drinking is necessarily the antidote. Plenty of people getting worse in misery loves company situations.