Isn’t it enough to just enter your password once to login, then receive a warning whenever you’re about to do something potentially dangerous?

If it’s such a big security risk, how come the most popular and widely used operating systems in the world and their users seem to be unaffected by it?

I guarantee, most new users coming to Linux from Windows/macOS are going to laugh and look at you funny if you try to justify entering your password again and again and again.