The anti virus industry boomed because of operating systems that were exceptionally vulnerable to attacks. Simply visiting a website could install software. The root cause of this problem isn’t that a user didn’t run third-party software. It’s that the operating system was vulnerable.
After many years of neglect by operating system vendors, there really wasn’t much of a choice in how to be responsible if you insisted on running a vulnerable operating system. Therefore, the industry boomed and it became status quo for users of these operating systems.
Or you could run an OS that regularly fixes vulnerabilities.