no need to format to install LTSC
you can modify a text file on an ent/iot installer to allow system and data preserving upgrades on pretty much anything, even 'home' or 'home premium' editions. i have one here that went 8 pro to 11iot--runs great, and have tested 7hp to 11iot as well. that was the test done before i did the one that 'mattered'.. still using it the test system, too. haven't bothered to redo it or reload anything else on it yet.
that's probably most the holdouts left. the absolute brutal persistence of 'upgrade' offers and win10 doomsday warnings on eligible hardware got most users to do it, even if they didn't really want to.