Instead of thinking about the constraints of mobile - of the things you can't do because the screen is smaller and there's no keyboard - we should rather think of the PC as having the basic, cut-down, limited version of the internet, because it only has the web. It's the mobile that has the whole internet.
The classic complain mobile vs. laptop is that "power users" can't do all their work in mobile devices. Despite hacking my way around some tasks to be able to do them in mobile, at the end of the day, I must agree. It's obvious that touch screen devices offer a superior experience by getting rid of a layer of abstraction (the mouse), but doing that, they also lose a layer of depth and complexity that allow for more polyhedric tasks.
That being said, I found Ben Evans' article extremely interesting, because he approaches the topic from a really distinct angle. Internet is evolving at an extremely fast pace, but this evolution is being build around a new generation of devices that allow for new possibilities, like camera, sensors... To get the full internet experience (not the full browser experience) you must have a mobile device, not the other way around.
PCs get a richer browsing experience, yes, but their are missing out in the new ecosystem that is being created outside of the browser. So a desktop / laptop might still be better at some specific vertical tasks, like editing text, creating video or programming, but they are far out the new wave that is already here.