I'm reading my October 2012 Sea Kayaker Magazine, Safety article. Whale lands on kayak, experienced (but injured) swimmers have to swim 2 miles to shore.

OK. I was an ocean swimmer, not very fast but strong enough. In dainty little Speedos I used to swim two miles in 50 minutes. Well enough.
When I consider a possible accident where I lose my kayak, (a whale landing on it would defeat any bulkheads) I see myself in the water needing to quickly decide whether to stay put, call the Coast Guard, wait; or start swimming for shore.
I can't imagine how long two miles would take in a PFD. Take it off and use it as a paddle board? Probably not much faster. I've got a near world class kick--if I'm wearing fins. Bare feet--I can actually go backwards.

The PFD has all the gear, radios, extra hat, gloves, knife.... I always wear it. Knocked on the head, no PFD is going to keep my head out of the water. So they aren't perfect, but for winding up in the water with no boat--they're pretty effective.

An ideal solution might be . . . . .
1. If the PFD could be also used as an effective (streamlined) paddle board. It would have to work first as a life jacket, hold all the safety stuff, but if it could also be configured into a paddle board--it would facilitate swimming ashore. (It wouldn't have to be larger or more buoyant than they already are. The Speedo kick boards for swim practice have more than enough floatation.)
And 2. If attached were a pair of fins. Anything from the Speedo kicking practice fins to much longer scuba fins would make anyone faster and able to travel longer distance than arms and wiggling feet alone.

My final point is that even if one is waiting for the USCG to come to the rescue, kicking towards shore or even in circles will keep a person warmer than just waiting--even if one is swimming in place (I've experienced this in workouts. Treading water in one place isn't as warming as swimming/kicking. Even to the point of exhaustion it isn't. Ever done the 'hold your hands in the air and tread water'?)

Just thinking.