On a typical PC, installed software has even more permissions than a browser extension, and all any malware author has to do is write their own keylogger or upload the browser cookie database. Sure, it's a little more effort, but I think the only real advantage that malicious browser extensions have over native programs is the discoverability and auto-update Google and Mozilla give them "for free".

> It doesn't ring true for installed software anymore — "virus scanners" have gotten to the point where they just work for most people

... by allowing software from big corporations not matter how user-hostile it is while randomly flagging/deleting harmless software make by individuals/smaller groups who have not paid the protection racket.

The AV industry is a scam.

> desktop software is more difficult develop (for your average hacker wannabe)

Desktop software can be written in the same languages as webshit and more.

> and has far less valuable data to go after

All data available in browsers is also available to native programs running besides.