Sticking with one standard only would mean no progress in A/V technology whatsoever.
As for true standards these days, I guess it is - sadly - still mainly mpeg-1 & 2-based formats like VCD, SVCD, DVD ... (yeah right, please flame me!
). They might not offer the most advanced features, but they do have one advantage: definition of a container format plus definition of a media/disc structure.
The lack of these structures is what - to my mind - precludes the universal use of mpeg4-based formats like divx. These might be fine for PC or HTPC use ('cause those platforms offer an unrivaled flexibility), but standalones are bound to fail to some degree. Talk about different codecs (like divx 3.x support), menu structures or selectable subtitles ... "divx certification" currently does not offer any solution whatsoever to this.
Formats like WMV or RM are proprietary and - hopefully - not close to ever being widely adopted for universal use.
Please note that I don't want to belittle mpeg-4-based or other formats, it's just that - to me - they are not a viable universal standards right now.