I think a minority should make itself compatible with a majority (just as in cultures/countries, and heck, just software anyway, you aren't going to release OS/2 software today, do you?). A Mac (a minority) being able to play PC formats (a majority) makes more sense to me than a PC-user being required to install some player coming from another minority culture. And if a xplatform solution must be made, let it be designed by some independent open-platform people who'll optimize it for all CPUs and systems, let them make sure every standard mediaplayer has its codec built-in and let it just be a codec, not some over-GUI'd player no-one wants to use.
ohwell, €0.02
ohwell, €0.02