That can help you make more efficient use of bandwidth and TX power, but doesn't come anywhere near making a free-for-all spectrum workable.
The carrying capacity for wireless customers (and carriers) could increase to above where it is now, but not the point where frequency coordination is unnecessary.
> but doesn't come anywhere near making a free-for-all spectrum workable
Why not? The ISM bands haven't become unusable even in densely packed residences with large numbers of Netflix-streaming cable cutters. Yes, cell phone towers have a longer range (which puts them at a small constant factor disadvantage), but they are also professionally maintained and can therefore make use of directional antennas and beamforming which gives them a constant factor advantage proportional to investment.
We have the technology to provide service to any reasonable density of people. It's a matter of cost, not scarcity. As opposed to, say, healthcare, this is a problem that markets should be very good at solving.
The carrying capacity for wireless customers (and carriers) could increase to above where it is now, but not the point where frequency coordination is unnecessary.