Labour intensive to round them up, test them, and design/build custom circuitry to hook up a pile of dissimilar panels. Then you have a pile of near EOL panels

Labour intensive to round them up, test them, and design/build custom circuitry to hook up a pile of dissimilar panels. Then you have a pile of near EOL panels with reduced output and reduced reliability that is unlikely to ever break even. When it falls apart there will be no money to ship them back to the landfill. So in short, it's a roundabout way to dump them in the desert.