Why can't the rate requirements be consistent city-wide and still have similar effect? Or, if the concern is really a flooded supply, have an incubation period

Why can't the rate requirements be consistent city-wide and still have similar effect? Or, if the concern is really a flooded supply, have an incubation period that doesn't favor incumbents? Surely it's clear that a law favoring the more popular company based on demand alone is actually worse for drivers and consumers by reducing choice for both of them.