Oy vey. You're objectively incorrect. It's definitely a Microsoft issue. They use the old OS upgrade procedure to do quarterly updates now which means if it finds a Users directory it will rename it to Users.old and make a new one. However if it does two upgrades in a row in the background without telling you the old Users.old will be deleted from your disk.

Now all it would take them is a second to check the sizes of both and not remove the one with actual data but ya know that would be a actual useful feature.

And before you complain about to me about my "setup"... The scenario I described above is entirely common in IT departments the world over.

Now please stop blaming victims and start blaming the people that have the power to change things.