I don't know what Americans throw in landfill but in England there's plenty of furniture or working electrical items that end up in landfill (or the modern equivalent).
But not if they were on craigslist in the beginning and apparently there are buyers. From what it seems to me, he just tries to be the fastest buyer rather than taking things that can't find buyers
I don't think he takes landfill material since he is able to sell it on craigslist for money only a day or two later.