Out of the following browsers: Firefox, Chrome, Safari, Opera and OmniWeb only Firefox runs on many of the distance learning software (such as WebTycho at the University of Maryland or Blackboard). This is not as narrow a market as you believe and until the others fix those problems Firefox I think we be dominant on Mac machines.
Yeah, you should write those websites and tell them that standards exist for a reason. If they follow standards, it will work on every browser.
The reason we got into the mess we did with the Web is precisely because browser vendors were fixing the mistakes of web developers. The trend has been moving to the opposite, thanks to a lot of work by the W3C, please don't try to bring us back to the web dark ages.