I assume you do realize you can still do a clean install (on old CPUs, instead of hitting upgrade, because that's what OP meant.
When you deny ordinary people the easy path of an upgrade and force them to do a clean install (because "security"), you induce the vast majority of them to avoid the migration pain and just buy new hardware, with the new OS preinstalled. If this isn't a way to force people to buy new hardware via software, I don't know what is.