I think you should also consider the exceptions and borderline cases:
And you can argue that people go to third spaces to increase their social capital — think of it as more opportunities to network in business or personal settings.
Some might, however I've personally noted that those who've 'made it' don't do that. They 'work the room socially'. That's included presidents I've met by chance at universities, high-ranking members of the UK's royal family (once got served by one in the university student bar!), good CEOs, good managers, military officers, etc. You can argue that it's faked, certainly managed in some cases, but those who do it know 'on which side their bread is buttered', as we say, and who provides the services they need. And in some cases there's no prospect of personal gain for them.
And I could report the Argentinian ambassador, the consul, and the vice-consul. I could report all of them who pretend to be tango experts.
Ah, but none of my encounters claimed to be AT experts! In fact, most of them were (apparently!) interested in comments, open questions, advice, information, feedback, socialising. They engaged, rather than standing aloof.
It was quite amusing with the previous Argentine ambassador to the UK. He didn't dance tango, and while he was the host and used to being the centre of attention, at the milongas hosted there he was simply a bystander.
I think that’s part of growing and using your social capital. Lube and bridge. You use it to interact with other who know who you are, maybe get perspectives that you normally wouldn’t in a boardroom ( lubrication ). Or you use it to reinforce the weak connections or create new ones ( bridge ). A recent example I saw was a teacher who taught at a university meeting the president of the tango club of another university at the dressing room of a milonga. They both were pretty high social capital in their own scenes but now this new bridge or connection makes going to the milonga worth it.
Few places here would qualify even on those grounds, except public spaces such as parks and playgrounds.
Yes, it can be. I've also known of some who are incognito, but, as you say, getting a perspective they wouldn't normally have.
Oldenburg was sometimes less pedantic! See article by Oldenburg and Christensen for Unesco. But sociologists have to earn their crusts with investigations and articles, so it helps there if you can define things which are, and aren't 'third places'.
That's a big part of the problem, according to literature I've read on the subject. In recent decades, there are ever-fewer places where people can congregate for free, and those places tend to be further from homes and workplaces than they used to be. The problem is especially pronounced with kids, who have even less money and even less freedom to move.
Roblox.
It seems to depend where you live. From experience with a relative in Stockholm, the provision there is really good - especially with children - library combining games, theatre, play areas, internet, coffee, lunch (fika!). Finland also seems to be good - anywhere it can get really cold so you need warmth and protection from the weather.