I'm gonna guess, it's economics? Sounds like a good idea though.
There's more to it. We have too many laws and the "wrong" laws as it is. I don't know about the rest of you but I don't want the government sticking their noses into what I wear...and that includes seat belts and helmets. If someone wants to wear some sort of radiolocation device (they've been around for a long time), then let them. I don't know of a law that prevents them from doing so.
Hey on second thought! If the device records the dive profile and is capable of radio communications we could ticket folks for doing dives that the government doesn't think they should do...how cool would that be?...you went too deep/long, that'll be $250...your ascent was too fast, that'll be $150 and your diving "license" is suspended until you pass a $300 safe diver update at you local nanny state government office.