[JohnTHaller]

Most of the issues Windows users encounter aren't viruses and the like that you're thinking of in the Mac OS classic, DOS and Windows 9x days of old. Those could self-propogate, infect apps, and be carried from user to user.

Most of the issues today are about money or reputation.

Adware and spyware makes money for the publisher, so they target areas where they can do that. It's actually legal and semi-legitimate. It's an annoyance for the end user, of course. A freeware publisher doesn't make any money from their app but they can make money from bundling an ad replacer, search engine replacer, browser extension, etc with their free software. So, they do.

Malware follows the same trail. You can distribute cracked software online over torrents like Photoshop and the like but sneak your remote-controllable malware into it. Then you get more installs you can use to direct a DDoS bot attack or to watch for and steal financial details from the local machine. Maybe look for the default install of a cryptocurrency client and grab the local wallet, for instance. Note that this is more difficult on both modern Windows and modern Mac than it was back in the days of Mac classic.