In my days shooting film, I always traveled with four camera bodies. If you think about it, film bodies were comparatively cheap. (An EOS1n cost about $1400, compared to my 1Dx which was $6700. The original 1Ds cost me close to $9000!) Other than primes overlapping with zooms, I only travel with two digital bodies -- my 1Dx and 1ds Mark III. Since all my glass are "L" lenses, I can't afford backups to those. I've often thought of going with a 2nd 1Dx, because the camera is so sweet to shoot with and I like the ergonomics. As it is, 95% of my shots are made on that body -- hence why I keep holding out for Canon to do something significant. Maybe I'll bite the bullet and go with a 2nd 1Dx, because, if I do, you KNOW Canon will finally release something. One thing Canon use to do is release equipment in the amateur market to try out new technology, which after refined, they'd put in the pro bodies. (Almost the opposite of Nikon.)
I still assert that Canon, for their lip service, has ignored the pro market for a long time, choosing amateur and cinema over the still pro photographer. Where Canon does shine (at least until recently) is the CPS program. From all I've heard, much better and faster service than their Nikon counterpart. No such program exists for any other brand (that I know of) -- Sony, Leica, you name it. But, again, where I disparage Canon is even the CPS program is gradually turning it's back on pros. Originally, to join CPS, you have to show published work, show you were in fact a working photographer. Now, it's pony up the money and have a certain level of equipment (so in theory, any well equipped dentist could join). But what's worse is, even paying for the service now, if you say to them when sending in your 50/1.2 and a 1Dx, "Hey, it's not sharp. It's also back focusing", you end up with an $800 bill! (True story from six months ago.) If I'd sent those in for cleaning, they may or may not have caught the problem, but IF they had, it wouldn't have cost me anything since it was a "clean and check" service. Oh, and the 50 still sucks big time. (I'm getting rid of it and buying a Sigma 50 -- rented for my last shoot and a truly sharp lens.)
Unless things change dramatically, after using Canon since 1980, I believe I can say, they've abandoned the pro still shooter.