> I suspect designers deliberately harm UX in an attempt to drive away unprofitable power users.

Considering how much things can be achieved via about:config registry in Firefox, then you're probably right. Not sure if entries can be still loaded with userChrome.css and userContent.css - back then I was using these to preconfigure browser for friends. These could be dropped into freshly created profile (via -P switch, without launching browser) and act like sorta "answer files".