The whole don't be an idiot thing doesn't work well with most people. Most people just gøøg|€ everything and most likely don't have a clue when they're being sent to fake sites that will give them viruses. And some of them will even see macrohard defender essentially saying "Hey! You Fucked Up!" and ignore it because they surely know better than a computer.
I personally like to think that computer literacy right now is similar to back when people were just starting to push for everyone to be literate. Big difference is phones destroying that effort for computer literacy by oversimplifying everything.
I haven't run anything other than free Windows defender since it was available I believe in Windows 7. Never had a virus or anything malicious. Don't download files that you don't know the source of. Don't click on mystery links. Don't visit insecure websites. And as mentioned, keep your system up to date and you'll be fine.
I worked geek squad for years. The vast majority of malware was people downloading free games or free software and then not checking the custom install settings to uncheck the "install McAfee security scanner" or whatever toolbar and redirection it was at the time.
I now only run Linux, but that's a change within the last 4ish months. Prior to that I was in Windows. And I work as a sysadmin and our network it all Windows on defender, granted, paid Defender and other security.