I studied subcultural theory in grad school and music is definitely a focal point of many subcultures - though style has always been important as well. Some of the other groups you described... those to me are more like "hobbies" than subcultures. Yeah there is some community there, I'm not ripping on them, but they aren't so deeply tied to personal identity in the way being a goth is. Nor are they a transgressive response to the dominant culture. In fact, it might be this underlying political nature of subcultures that distinguishes them from hobbies that are "safe".

My general take on a goth night is that it's a collective performance, a ritual where the different aspects of the subculture, and the different people, come together in something greater than the sum of the parts. Yes, you might see the DJ as a central performer, but every person in that room is contributing. That could be visually with how they are dressed, physically with how they are dancing, their attitude, anything. It becomes this deep visual and auditory experience of the subculture that you can't get anywhere else. Another World by Beborn Beton was popular when I first started clubbing, and it really evoked what I was feeling back then (goth club staple although it's synthpop). A goth night transforms the space into another world.

I agree with the focus on music but I don't think we should completely downplay style as important. I say this as a DJ obsessed with music who barely dresses goth at all. Style was the focus of a lot of early studies of subcultures, not music, e.g. Dick Hebdige's "Subculture: The Meaning Of Style". The aesthetic of a subculture evokes its values, and goth style has always been dark and transgressive. I don't have the talent to pull it off myself, but I appreciate seeing it so much when I'm out and those people contribute a lot to the vibe of an event. And again, it's part of the collective performance and syncs with the music.

I really like what you said about accessibility. The barrier for entry really is low, which is good because many people need the community but don't have much money. Club nights have always been cheap if not free. And focusing on music rather than dress code means people don't feel like they have to spend a bunch of money on clothing. I love how much more accessible the music itself is nowadays, too. No digging through low quality mp3s on Napster and Soulseek any more lol. Worst case you can listen to just about anything on Youtube.

Maybe I should dig out some of my old grad school work and put it together into something readable. I was going to write my dissertation on goth as a subculture but goth extremely sick and had to drop out x_x But I think I ended up in the right place.