Obviously the future is subject to change, whatever one might now say. But to phrase this issue differently: there are resistive touchscreens and capacitive screens. Resistive screens support styluses, capacitive do not (except special ones, but that's a bad idea).

Now, people seem to prefer capacitive screens in general. To ship a capacitive device, having stylus UI elements is obviously a very bad idea. For a platform, there can of course be many different devices, with differing screen technologies. But branching the UI software would also be a bad idea.