http://www.usatoday.com/story/tech/2013/03/06/apple-google-microsoft-hewlett-packard-dell-ipad-iphone-android-ios-samsung-galaxy/1946325/
Uhm My correction 4 times as many mobile devices are sold then desktop based systems actually. As for being the 'niche' system builder, that is like any other 'product', cars, planes, boats, electronics, etc. all are going to be 'easier' for someone to customize and build 'what they can't then from prefab production model product. But it is more costly over all for the person when you calculate the 'real' value to include the time in comparison, the mistakes 'self builders' have to replace twice the same part due to problems, man-hours in working to get it to the 'way I want it', etc.
Though it is unfair to compare a desktop 'building' to a laptop production and say "Laptop can't keep up", because your talking apples and oranges, your not buying a laptop to 'build' out of like a hobbist like yourself (again niche not common poster like the OP which is generic Joe/Jane User whom doesn't know how to spell Unix much less what a Unix IS), your buying it for the portability, east, and all in one packaging it provides. It be like complaining Apples don't peel as easy as Bananas nor are as soft and tasty as a Banana is, your talking two different things here.