I don't know where you dive, but down here the majority of divers 1. use a flag, 2. know how dangerous it is out there on the ocean with boaters, 3. think there needs to be something done about it. The only ones who might think otherwise are totally noobs who haven't experienced a near hit.
Majority.... That means 51 do, 49 don't. I can tell you first hand, I see dive boats in Boynton who routinely put divers in the water with NO FLAGS. Those boats allow divers to send up a sausage. While a dive flag is a recognizable symbol and has legal standing, a sausage inflated correctly or not, is no more than debris in the water. Also, many dive boats; commercial and recs alike, fly dive flags from the boats rod holders in the stern or other low points, where the flag is obstructed from view and can only be seen when an approaching vessel is quite close. additionally I often see boats displaying an undersized 12 inch flag. It's hardly visible from a significant range. Even the required 24" flag can, at times, be difficult to see. On a regular basis I find divers with broken dive flags the are lying flat on the surface. And it is also common to see snorkelers or speros operating in the inlet with no flag at all. A welcome change to the law would be a 24 inch flag for divers and a 3x5 ft. flag for the vessel.
Yes there are times when a responsible boater in will inadvertently approach a dive flag. We do all look out for them, and prefer to keep more than the required distance. When ocean conditions are more "sporty" Flags that are 12 inches off the surface can be impossible to see. Often times commercial dive boats operating on the Pompano to West Palm reef line, will string divers out over a mile! Captains would be well advised to stay closer to their divers, especially in a region that has over 50,000 registered vessels. Along the beach, every thing is compacted and divers are too challenged by paddle boarders, windsurfers, kite boarders and personal watercraft. When I surface I am always listening for the sound of boat engines.
My diver flag is atop a 48" of PVC, making it much more visible to approaching vessels. Who ever is piloting my boat when I am in the water knows to stay between on coming boat traffic and my flag.
To simply blame boaters is incorrect.