If a new tenant can afford triple the rent then they are (at least) 3x as productive. Why do you want to reward less productive businesses? Do you also enjoy working with coworkers who are have 1/3rd the productivity you?
VC funding distorts this, since at that point what you can afford is no longer based on productivity, but how good you are at convincing investors. As a customer of the cafe, you're no longer serving my interests at that point since that has nothing to do with my experience.
Also, I would like to reward the service-oriented business that provide me the most enjoyment regardless of their 'productivity,' or, to put it another way, my (as a customer) enjoyment is exactly the 'productivity' that should be measured, not how much rent they pay.