I hear what you both are saying....however, if it was set up that if you choose to open a second business it would have to be a public gym, then this would eliminate that from an option.
No, it wouldn't. Because what would stop anybody from setting a very low max capacity and having all of his fighters going into the gym? It would be a public gym, but only formally. Effectively it would be run exactly like a private one and end up being every bit as exclusive.
BTW - There not being enough public gyms (safe for maybe Tokyo and Montreal right now) is not even the chief issue of public gyms. Given the current demand, there are enough public gyms in most places. Public gyms suffer from being effectively cut off from a big part of the most active player base. It is a balancing issue resulting from the turned off locations.
Check the following link, to understand what I mean by this:
The problem isn't offer, but demand! Enforcing these busineses under such circumstances would be heading in the wrong direction.