Windows has file level security and doesn’t require every user to run as an admin, in fact MS advises users IN the OS to use the security and do their normal usage under low powered accounts. Windows don’t because Windows user don’t want to bother. Windows users are like a world where you just sit down and go, if they want to install apps they want to install apps they don’t want to have to login as an admin to install the apps and then log back in as a normal user to use them. There’s absolutely nothing about Windows that forces them to run as admins, they just do it. And really even if they weren’t running as admins they’d still find ways to hose the machine, they’d just login as a different account to do it.
Just try starting off with a standard windows install from an OEM and try to go for a week without being Admin. You'll quickly see that Windows was never designed to run in low powered accounts.