Why would it slow the computer down. Maybe you could explain that to me?
But yes you are right that it would be counter productive in that for every feature ms offers they must also provide support for that feature. Which would be a waste if it was something only 0.1% of people would use and the developer resources could be better put to use somewhere else. Why waste limited/valuable developer resources on something no-one wants?
Hey, that sounds like the economic problem - limited resources, unlimited wants.