How do you use the photographs you take? Do you print them? Sell them? Do they ever even leave a computer screen?
If you do print your images, what is the biggest print you have ever made? For me, it is 20" x 30" for my piece The Comedown. I photographed it on a 24 megapixel crop sensor camera. How many people will honestly be printing their photographs larger than that? My guess: very few. So why is it that many cameras' biggest selling points are their obscenely high megapixel count? Most people will NEVER need resolution that high in their lifetime. And yet, people spend thousands of dollars on a camera that ultimately makes you a less creative photographer.
In modern photography, we are obsessed with image quality. After all, what good is a photograph of a model when you can't see the microscopic specs of shit on their lingerie? Forget lighting and composition, just make sure your resolution is high enough that you can see the shape of the fibers that make up your subject's shirt, right? Is resolution really what makes the image? If you answered yes, you should probably reconsider why you take photographs. The truth of the matter is that the more brain power you put into making technically good photographs, the less you are putting into an image that is truly great.
I might understand if you were shooting for wall-size prints, or exclusively for commercial purposes. But for the rest of us, how many people can objectively say that an ultra high megapixel camera is the right tool for the job? These days 20 megapixels is considered on the low end on the spectrum. But there are so many great cameras out there that could be written off entirely simply because they fall below that number. Take the Ricoh GR series. The most recent model has 16 megapixels, yet it is by far one of the best digital cameras out there for candid photography. But because it's specs don't match up to the new Sony A9, it most likely isn't on the radar for most photographers. What really gets to me isn't that megapixel counts are getting unnecessarily high these days, but that people put so much value in them.
My advice: learn how to use your camera, and forget you even have it. Think of it as an extension of your eyes. Doing this has helped me to understand that there is much more to photography than image quality, and as a result I now put less value in my camera specs.
One great way to do this is to use the sunny 16 rule. For the uninitiated, the basic idea is that you set your shutter speed equal to your ISO(I recommend ISO 400 - 1000), and adjust the aperture based on light conditions. For sunny days, use f/16. Sunset = f/11, clouds = f/8 and so on. Do this, and it could totally change the way you shoot.
Or you know, just shoot film.