The very compact social dance of the central Milongas was/is of necessity and also isn't necessary for tango. You may prefer it as a personal style and I wouldn't argue with that.
There are quite a few places in the UK where the practice of a compact
social dance would enable dancers to continue dancing despite the crowded
conditions. Instead the ronda stutters, stops, starts, gets congested
etc., etc.
These are usually milongas run by teaching organisers who do not teach
the dancing helpful, even necessary, for such conditions. Nor do they
restrict the attendance to numbers appropriate for the dance they teach.
I do think that the re-establishment of proper practicas would greatly improve the learning of tango as a social dance - I'm also confident that no one would turn up. Teachers working with students in a class/workshop or 1-2-1 setting is here to stay, but if you happen to hang your 'authenticity' hat on the hook of the method of learning, then tango died out everywhere a long time ago.
No need for any "authenticity" hat. It's a dance that teachers mainly
avoid teaching possibly because it needs more doing than teaching.
Six lessons or so for women, maybe 8 to 12 for men though all the numbers
depend on aptitude. You have to learn to dance though.
If your hook is the physical location, then the dance doesn't travel; and if your hook is the particular style of dance, then you should stop using the generic name for your dance, and name your style unambiguously. If it's that you only drink wine from the Malbec grape, or that the ladies shoes need to be a certain brand, or that ....
The hook is not the physical location, the hook is the dance itself.
And that is all that matters.
I've always been prepared to name my style, and have done previously.
I wish others were as it leads to such confusion when talking about
technique which are so different from one style to another.
Argentines call all indoor sociable tango (and their view of sociable
depends on the floor conditions) Salon. But you know that. More
specifically it's "Tango del Centro", maybe Apilado but I'm avoiding
Milonguero. See Tango Voice for all there is to say on styles.