Apple (among others) have successfully pushed for video and audio to become first class elements of HTML (HTML 5) instead of being relegated to browser plugins. They pushed for the video and audio encoding used to be ones that are open standards with low-cost / no-cost encoders. They are doing similar things with CSS animations, etc. with the obvious goal being to have these capabilities codified in an open standard that all vendors can participate in instead of a few.What did apple open? again?
Anyway Apple during the last decade has made large efforts to covert their "systems" over to use open standards as much as possible getting away from proprietary codecs, etc. In fact Apple is one of the reasons that H.264 and related codecs are so prevalent on the web today despite the best efforts of some vendors.
Why is Apple doing this? ...because it levels the playing field and undermines their main competitors...