The new nikon is better than the canon 5d mk iv in almost every spec. Is there any chance canon will release a firmware update that adds new features in order to be competitive with the nikon? Have they done anything like that in the past?

I don't have an answer to your question directly,  but I do have to say that Nikon and Canon's top range DSLRs are always worthy
competitors to each other and I don't think that a firmware update is really going to make or break your photographs.  

So I would say, don't sweat it.  It's just not going to make much of a difference.  

I'm a Nikon guy, with both a D800 and a D810,  and I have enormous respect for Canon's offerings.    I'm sticking with Nikon, but
that's because I don't want to duplicate the expense of duplicating my lens collection in a different brand when any camera we're
talking about is capable of better photography than I am.

If I had by chance started out with Canon instead of Nikon, I'd have done the same thing.  Stuck with Canon, while respecting
Nikon's offerings and not putting either brand down in favor of the other.

Actually I'm not planning to get a D850.  I may be in the minority but I think that not including a built-in flash in it was a mistake.
I use the built-in flash on my D800 and D810 way more often than I want to bother to attach an external flash.

You're right, i highly doubt it would make a difference in my photos. But it is still ridiculous that the cameras are the same price and the nikon has so much better specs. It seems like several of the differences could be addressed with a firmware update.

If anybody was new and trying to decide between canon and nikon why would they go with canon? The brands have always been close but the d850 is clearly superior, at least on paper.

The next Canon to be released will probably look better on paper than the D850, too.   This leapfrogging back and forth between top competitors
is just the way the game is played.   Intel/AMD.   Nikon/Canon.  Android/Iphone.    Expect it, and be glad for the competition,  because it's what
drives the manufacturers to make better products.

Now that I've learned a little bit about photography,  I'd let lens choices guide my camera buying.  If I were a professional wildlife or sports photographer
I'd probably go with Canon because they seem to have the best choice of long zoom (and big price tags, too!) lenses for those applications.

Check out any major sports event and look at the photographer's section.  Lots of white lenses there.  I suspect there's a reason for that.

IMHO, specs aren't the only thing someone starting out should be considering.  Lens selection and other system accessories, ergonomics and viewfinder, should be considered as well.  Canon and Nikon tend to leapfrog/ one-up each other a bit with regards to camera specs, so I'd be surprised if Canon doesn't release something within a year or so that makes it the new hotness instead of the D850.

We have things so incredibly good WRT the state of digital photography and the available choices, it's amazing.



edit - I type slow. 

The 5DIV is no slouch by any standard.  There will always be newer and "better" bodies released.  Pick what you're comfortable with and shoot.  I love my canon stuff (including my 5DIV), but have a several friends who are Nikon fans.  Ultimately, if you know what you're doing, the body isn't going to make or break your photos (for the most part).  I still occasionally use my 5DII and get great results.

They already did an update with the 4k update a few months ago. (C log ?)

I am kinda curious on where cameras will be going in the next few years.