Unfortunately, there is something far easier and cheaper (from the end user's perspective) to duming in a controlled landfill: dumping in random places.

It's been a long battle in many places to get people to properly dispose of their trash in a proper way, it's still way too easy to revert to prior behavior. In many places in the US, people have to pay a private company for disposal or haul their trash to a landfill (usually in more rural areas). So it's a very visible cost, making savage dumping more compelling.