Well the way that our society works now is that we don't ''officially'' give people privileges or cause them to be disadvantaged based on their gender, sexuality, age, race, religion, physical ability etc, no - we just give people privileges or cause them to be disadvantaged based on how much money they have. How progressive of us! /sarcasm
So the only 'solution' to overcrowding that is actually realistic within a society which favors the rich, would be for the tube to just do what train companies do and have 1st class carriages = paying extra for personal space. I personally would rather that didn't happen but I'm surprised that it hasn't been implemented on the tube because they could, if they wanted, charge really extortionate rates for first class seats, rake in a lot of money and cram more in cattle class.
No one is going to give you extra space based on anything other than how much money you have.