Rather I suggest a market solution: since carry-ons increase plane weight and are a hassle for passengers, security, and airline staff all, why don't the airlines reduce the cost of the flight for those who bring no carry-ons? Maybe by US$50?

This would probably be enough to incent people to bring fewer if any carry-ons, thus speeding both boarding and deplaning. It also would probably increase flight security.

Generally unless it's an overnight trip, I FedEx my luggage to my hotel anyway and bring only my purse.