In war and in photographic equipment innovation movement is all. Failure to move is death. If makers stop innovating sooner or later the market stops buying, money dries up, R and D (which creates the next generation of innovations to sell so the cycle can continue) then stops and shortly after so do the production lines. Then no more Nikon, Canon or whatever. At least not in their current form.
So they will keep finding new reasons to innovate. Or, as with the megapixel war which seemed to have a short armistice, they will recycle the same old reason on a new even more mind boggling scale.
I have said before that I recall reading various articles in the early days of digital (say late 1990's early 2000's) that to match film in terms of information captured digital sensors were going to need about 25 megapixels, maybe 30 mp at a stretch. Given that, at the time sensors were around 1 megapixel, that was quite a big "ask" back then.
But less than 20 years on, and we are now there in terms of every day products being marketed and well beyond that in terms of the cutting edge technology now on the market or soon to be.