Egami has shown that Canon has filed a patent for an ultra-wide angle zoom:
Description and self-interpretation of the patent literature
Patent Publication No. 2014-10286
Canon users have been left out in this focal range for quite some time. With Nikon and their legendary 14-24mm f/2.8G ED and other third party offerings filling up the gap in the market. Can Canon produce an optically superior lens that also has such a shallow depth of field? Until they do, the only wide-angle zooms that Canon makes that come close are the 16-35 f/2.8 L II or the 8-15mm f/4L Fisheye.