Certain workflows prefer non-queueing, for instance the throng empowers the bartender to load balance different groups, delay drinks to over consumers, etc etc. So other cultures can have those workflows in places we might not expect, that is not necessarily a matter of respect. In pub culture, queueing disrespects the bartender.

You're conflating efficiency norms with respect norms. Never mind that the core reason for no queues in bars is space efficiency and historical norms, allowing the bartender to select regulars, better paying customers, etc. without being stressed for time.

But in any case, your edge-cas applies when someone exists to manage the queue. That's not the case for e.g. elevators, self-checkout lanes, DMV lines, or, I'd argue, that vast majority of queues encountered regularly.

It depends. Many places in the UK have a tradition of "virtual queuing" at bars; they don't stand in a line because that would usually block the space, but everyone remembers who was before them. Usually the barkeep remembers as well, but sometimes they ask "who's next" and people defer to those ahead. But load balancing also happens.