Your logic on the economics of these parties and how they worked is off. Too much analysis of this from the Indy point of view. The Iggy parties of past years were dominated by agencies and MP ladies. The ladies didn't make the call on whether to attend- the agency owner did. They got publicity and free advertising on MERB. I would suggest you go back and read some of the party threads. Let's please stop the revisionist histories and economic analyses.
Due to the success and size of the parties, some indies, who had been invited, started attending. From what I saw they picked their spots. I can remember one lady (hate to say this but I forgot her name, but she was great- 5'11" black lady from the Caribbean, I saw her maybe 3-4 times- someone remind me of her name). She wasn't really into parties but came to a couple of the Iggy parties. She didn't stay for the whole of the party. At one of them I persuaded her to come and told her I would be there. I bought her a number of drinks and she ended up getting drunk. This was one of the Lord Berri parties. Anyway my sidekick who came to the party excoriated me for not getting her a taxi or Uber after she left the party on her own. And Iggy was not happy with me either. I didn't actually see her leave (or maybe I did), but because I had gotten her drunk I did feel responsible. I texted her and apologized and the next day we texted and she made it home fine. I think she took the Metro. The other party she came to she didn't stay long, just long enough to be seen. She wasn't comfortable and felt it was a meat parade, which in truth is kind of what it is. But she understood it was good for business to bite the bullet and be seen. The party where I got her drunk she stayed longer because she was mostly sitting with me at the bar. But after she got drunk she actually gave some other guy a grinding lap dance right at the bar. This was kind of out of place with her personality and one reason I got my ass chewed out for not getting her a taxi or uber.
If you are buying drinks and getting someone drunk please keep this in mind.