In many ways, your perception is correct. Increasing image quality IS a numbers game.
I purchased a Sony camera in 2000 that cost several hundred dollars. I thought the images it made were amazing. It completely blew away even the very best I had ever done on film.
Eight years or so later I purchased a Nikon D7000 and a 50mm f/1.8d lens and thought THOSE images were amazing.
I've always shot full manual since around 1970 so I am a lot more in control of my camera than folks who just take snapshots. But then I switched to RAW and started post-processing using Lightroom. WOW! What an improvement.
Since then, I've added a Nikon D810 which completely blows away my D7000. Later, I replaced my "plastic" 50mm lens with an amazing 30 year old Nikkor 50mm f/1.2 manual focus "nifty fifty" lens. Excellent glass really does make a difference. So I purchased a 20 year old Nikkor 35mm f/1.4 manual focus lens and stuck it on my D7000.
At this point, I really don't need more megapixels. And I don't think there is any better glass out there for my needs in the less than many thousands of dollars range.
But in terms of "the numbers game" you mentioned, digital cameras still do not even come close to having the dynamic range that the human eye has. This is where I see much more development needing to be made. When they come out with a camera that has roughly the same number of stops of dynamic range as my eyes do, I will be all over it. In the meantime I see small improvements in this area but camera manufacturers are mostly focusing on features that don't really effect image quality that much anymore. More megapixels at this point are only important to people who plan on making billboards out of their images.
Faster frames per second, better low light performance, ever higher ISOs and so on are, to me, unimportant bells and whistles at this point. I did NOT spent megabucks to purchase a Nikon D5 for that very reason.
As far as image quality and where one kit of gear is better than another, I personally feel that I make pretty decent images. Properly exposed, interestingly framed, in focus images that I hope tell a story. My gear is quite high end for a non-Professional.
However, Ansel Adams could take pretty much any camera including a point-and-shoot and put any of my photos to shame. Technology will only get you so far. A great tool needs to be in the hands of a great Artist (which I am not).
So, yes, it's partly a numbers game, partly a constant striving for better glass and constant skills improvement, learning how to use a camera in a way that will get the most and best out of it. That's why we practice photography and, at least in my case, will never master photography.