Less laziness and more waste of resources. Sending factory employees to locate the old mold and clean it (they need to be spotless) is a time and money issue. I'm hazy on how our molds work --some may be broken up into small, sliding pieces, so you can mix and match, but I think at least some of them are solid blocks of numerous small parts, which means you need to block off the parts you don't want/need just to cast the part you DO need. It's fairly labor-intensive. So they tool it onto the new mold -- tooling can take a long time for big stuff, but I don't think Minimate parts take very long.