Windows and macOS allow you to install software (most of the time) without being an admin on the system. You only need to be an admin if the software to be installed needs certain capabilities.
On Linux this isn't typical. You usually need to be an admin to install deb or rpm. Things are changing but it's not fast.
You mean, the Unix way of "you run your software from wherever you want" needs admin for installing software, while Windows doesn't?
You can lock Linux down so that normal users can't replace almost the entire system on their sessions. This is possible. It is also usually a lot of work.
THAT was their problem. before limux there was no permission management and everybody was admin.