I thought FireFox was such a positive force for open standards, in the days when IE was a monopoly.
But something happened. FireFox got to 20% market share, and they got a bunch of money (from Google) and fame. Then, Mozilla ceased to become an organization that was dedicated to an open web. It became, instead, an organization that knew better than the open web. It wasn't about implementing standards any more. It was about God's chosen web engineers determining what was best for the web.
The problem with Mozilla refusing to implement open standards that other browsers implement, is the same problem we had back when IE had disproportionate market share.
Chrome and Opera and Webkit don't suffer from this narcissism. They just get on with it and implement open standards.
Hooray for open standards!