A partial solution to the problem of plastic bags and other plastic products floating in the middle of the Pacific Ocean is to put a recycling charge/refund on these products that is redeemable — much like the system that is currently in place [in some states] for items such as soda cans and plastic water bottles.
If the supermarkets, superstores and regular stores charged 2 or 3 cents for each bag, and then refunded the money when the bags were returned, much of this problem would self-correct.
Bag boys would be more efficient, using fewer bags.
People would pick the bags up off the streets — some people do this for their living.
Put the incentive in and the people will self-correct much of the problem.