It's neither handheld or desktop, it's the pace of advancement. In 2005, it was a frustrating and nearly impossible task to use software made for Windows 95. I

It's neither handheld or desktop, it's the pace of advancement. In 2005, it was a frustrating and nearly impossible task to use software made for Windows 95. In 2016, it's much easier to emulate a 2005 environment. Same for mobiles. As the relative gains from each generation to the next taper off, there will be less to radically change from the ground up.