If you are flying legally - within the FAA mandated "Visual Line of Sight" (VLOS) restrictions, you probably don't worry about exceeding the range of your on-board video and telemetry links. 600mW on the 5.8Ghz video and 200mW on the 915 Mhz telemetry is more than enough to provide a strong signal when you can always see your aircraft.
But if you fly outside of VLOS...
I got my FAA part 107 certification only because that gives me the right to apply for a waiver. The FAA grants several types of waivers. One type lets you fly a drone at night. Another lets you fly higher than 400 feet in certain areas. And one lets you fly further than VLOS. The last one is the one that I'm interested in. And while there is no guarantee that I will be given such a waiver, my application for that waiver must have some sort of proof that I can fly my drone SAFELY when flying out of VLOS.
Since my craft will be flying out of my sight, I need to prove that my aircraft can reliably fly autonomously (using GPS for guidance). I have proven this to myself hundreds of times. But the FAA will want to know what happens when certain failure conditions occur, such as loss of GPS, or obstacles in the flight path, and about the various Fail-Safes that I have in place. One important piece of information is always knowing where the aircraft is. And if it is not where it is supposed to be, is it possible to change its path?
If a drone is flying autonomously, and goes out of radio range, the operator has no idea where it is, what is in front of it, and he certainly cannot control its direction.
How great it would be if it NEVER got out of radio range!
I am very close to that solution. By using a 4G LTE signal from Verizon, I can stream live HD video from the craft while simultaneously sending telemetry (battery voltage, current, attitude, altitude and location) AND sending control signals back.
This gives me virtually unlimited range - at least where 4G signals are available.
By using this technique, as well as a few others, I think I can convince the FAA that I deserve the waiver.