New York City is helping the supermarkets handsomely since the five-cent bag charge goes to the supermarket, not the city.
What was a cost of doing business now is pure profit to the store. Five cents sounds like nothing, but remember it is double bag, so it become ten cents. The average customer has three bags, so that's 30 cents.
A supermarket has 1,000 customers per day, so 30 cents times 1000 equals $300 a day. Multiply that by 365 days and that means $109,500 more profit at our expense.
Plastic bags may not degrade, but what logic says that paper bags are not biodegradable? Soak it in water or leave it out to the sun and see what happens to paper bags.