I think it's quite a bit more complicated than this. The concept of disposing of something always existed, but for most of human history that meant just leaving waste where it fell or at most tossing it at the edge of the village.
It's only once larger settlements appeared that a need to concentrate waste in one location to avoid despoiling the entire area became necessary. This was greatly compounded with the invention of manufactured materials that don't biodegrade like glass and plastic. There was no other solution to this than to concentrate and bury waste so it didn't end up everywhere.

Voters think that though. Waking them up from the illusion may help.
Plus, honestly, most people drink their own kool aid so I wouldn't be surprised if our leaders did believe this despite all evidence. The desire to think of yourself as a good person can overpower most evidence.