One of the reasons ARM has succeeded over Intel in the embedded platform is exactly because it's a hodgepodge in terms of implementation.. Arm just designs the chip, they don't make it, they leave that up to others, who then in turn support their own chips by providing kernel patches - which has been amazingly successful for Linux (and incidentally the non-linuxy iPhone as well)
Not to talk trash, he definitely understands the kernel and software but the nuances of hardware development and what makes hardware successful or unsuccessful aren't in his core skill set. After all, way back when he could have picked any position anywhere he picked Transmeta.
A lot has changed since then but ARM has done nothing but help Linux. If your chip vendor has a poopy Linux implementation they'll sell less. If they have a great one (and great documentation) they'll sell more. TI's a pretty good example of an awesome ARM / Linux implementation, and.. there are less awesome examples..