IT has since upgraded Firefox a couple times, so I decided to uninstall Tabbrowser Extensions to see which of its features were now standard in the browser. So I uninstall it....and suddenly the browser is 10 times faster. My entire time at this job, I thought I was given a bad machine with not enough RAM for Firefox, when really it was just a crappily written extension that slowed down my entire computer. At least this is good news: I don't feel like I'm getting work done through molasses anymore.
This, friends, is why I don't like Firefox. And the offer still stands: I promise to like Firefox a lot more just as soon as someone can solve these concerns for me.