In the days of resistance controllers, a close match was essential. This is no longer the case with PWM ESCs. Generally, what will handle a lot, will handle a little. There will be some exceptions such as ESCs designed specifically for high performance where accurate low speed control is not a requirement, and a certain amount of coarseness can creep in.
A PWM ESC, by switching full-on and full-off, varies the proportion of full power offered to the motor, either by having a constant pulse rate and varying the length of time the pulse is "on" or having a set pulse length and varying the rate at which the pulses are generated. The motor is always offered the full power when the controller is "on", but if the controller is only "on" for 25% of the time, the motor gets 25% power, with speed to match. Provided the motor can handle the voltage, and the ESC can handle the current and stand up to the voltage, the same level of control is available over a wide range of motor and voltage with the same ESC.
Hope that makes sense.