I guess I don't get it.
I have always had to show my Drivers License when I pay for the rental if I pay with Credit Card or check, so nothing really changes.
I have to show my ID when I buy jeans at The GAP also when paying by credit card. Big Deal.
ID's are easy enough to forge anyway. Hell I had a few when I was younger and you couldn't tell the difference. It is just a false security blanket that makes people feel good that something is being checked. It doesn't fix or solve anything, but I don't mind.
Pilots IDs are a good idea, but again easy to forge. There is new technology out there that are basically "smart IDs" in that the Card has a microchip in it and requires the users fingerprint to be inplace for verification or authorization. As far as I know it is still in Beta versions, but could be on the market soon. Again, this isn't a fail safe method, because if you can get your hands on the chips, you could build your own.