[jogjayr]

> It's certainly nowhere near $5 a bag

Maybe not. It just needs to be high enough to discourage most bag throwing. Maybe that number is $2 instead of $5. Maybe instead of just offering you a bag at the counter and tacking it on to your bill, they make you go to the bag aisle and bring back a bag that you have to consciously buy (it has a barcode and they scan it); so it's a cost in annoyance rather than money.

> taxes and fees for street cleaning and parks aren't anywhere in that ballpark

It's not just street cleaning and parks. You're discounting trash collection, recycling and landfill costs. The costs of the city being less attractive (I don't know if it can be measured, but there certainly is a cost). The cost to wildlife and the oceans. Do all these add up to $5 a bag? I don't know. Would a $<punitive_number>/bag fee eliminate most of these costs? Probably. Could someone more creative than myself come up with even better ideas? Definitely.