Maybe there is no reason to use Firefox for the business?
IE actually saved me some time the other day. A client is using TinyMCE and wanted spell-check enabled. I thought this required a PHP script on the server (which is not going to happen, our infrastructure is not set up to run PHP), and that I was going to have to port that script to Perl. Turns out it can use IE's built-in spell-checker instead. Since the client only uses IE, the problem was solved.
This does not make up for the thousands of hours I've spent on things that work great in Firefox, Safari, and Opera, but immediately kill all scripts in IE. (The error messages are crap, and the debugging tools don't work. Nice!)
Last time I checked, Firefox and Safari have built-in spell checkers too (and both browsers probably had the feature before IE did). The only reason not to use Firefox is because it would cost too much to make all of the IE-only sites work in it.
Even if the apps already work on Firefox, it would cost additional time and money (creating/updating documentation, another set of security patches to track, etc) to support the new browser.
Even just testing all the apps on all the sites to find out if they are compatible with Firefox costs time and money.
IE actually saved me some time the other day. A client is using TinyMCE and wanted spell-check enabled. I thought this required a PHP script on the server (which is not going to happen, our infrastructure is not set up to run PHP), and that I was going to have to port that script to Perl. Turns out it can use IE's built-in spell-checker instead. Since the client only uses IE, the problem was solved.
This does not make up for the thousands of hours I've spent on things that work great in Firefox, Safari, and Opera, but immediately kill all scripts in IE. (The error messages are crap, and the debugging tools don't work. Nice!)