[donniefitz2]

I think some of this slowdown is due to reaching "peak sensor". Much of the frenzy back in 2007-2012 was due to big advancements in sensor technology, namely, low-light performance. But now, my Fuji X100, which came out in 2011 still shoots great images, even in low light. And my Fuji X-H1 will be very adequate for the next 5-8 years.

As camera sensors became better, the need to replace them with the next model diminished.

Much of what camera makers are now producing are features on top of already great sensor technology. I don't think most consumers care about these additional features.