And how on Earth would a touchscreen benefit OS X? Doesn't that overlap into the idea of an iPad being the same thing (minus the keyboard and trackpad)? Why design OS X around touch when you have iOS catered to that specific need?
It isn't so much that iOS has catered to the need. There were touch screen Macs ( after market ) long before there ever was an iPhone, iPad, or anything iOS device. That some users can't find some utility by using their fingers on a screen
iOS is much bigger than OS X. There is little, to no need to grow touch solutions bigger by adding a touch focus for OS X. If Apple needs a Chromebook 'killer' then all they need to do is put an Apple ARM solution from a iPad design into a laptop form factor. Done. Already have an OS. Already have the apps (even more so if roll out a 12" iPad Pro) .
Windows 8 ( and up ) brings in touch because legacy Windows apps, hosted data, and infrastructure bring all the huge inertia.
Tim Cook is doing a fine job as it is. A Chromebook, in my opinion, is a joke in this day and age.
Chromebooks (and Chromeboxes) fill a need for affordable personal computers. The whole Apple line up really don't do that. Apple's 30% tax and targeting of higher build costs is in conflict with getting computers into the hands of as many people as possible. Microsoft Windows tax wasn't either. That's why Chromebooks are there in the market.
Apple's push back against Flash and toward HTML 5 + javascript as a open standards based web app delivery platform was (and still is) a large enabling factor for Chromebooks. It isn't a joke. Chrome device can do effective work offline also. It is the speed and robustness of the HTML 5 + javascript stack that is far more important.
If have 1,000 kids in a school and can choose between iPads and $100-200 cheaper Chromebooks, then that is a difference of $100-200K. That amount of money isn't a joke for more than a few school operators.
Chrome devices were never intended to take over the whole PC industry. They are targeted at a very real subset.
When touch gets super affordable then it will be pervasive on Chromebooks. That is coming. It may take another year or two to arrive, but it will eventually.
Touch is more driven short term by the targeted Android app ports that are trickling onto Chromebooks. That may or may not work out so well long term.