Originally posted by MMVIII Excuse me, this might be your opinion, but I largely disagree.
The D500 can't even compete with the KP in most areas of the IQ. It has no IBIS and is left with a large lens portfolio, that will very likely be frozen at what it is.
Why on earth would I now consider a D500 if I wasn't in the need of it until now, while the K-3III opens an additional asset to a system that is strong in many aspects but had some room for improvement in regard to action shooting and moving subjects.
On the contrary, the situation seems much more comparable to the time when everyone in Nikon land was waiting for the successor of the Nikon D300 line but they wanted to lure everyone into the new hype FF DSLR, while Pentax brought the K-3 which many, also Nikon users, considered as a worthwhile continuation of the neglected Nikon line.
Same might be happening to the D500, it's an abandoned line, and there might be some who actually liked it...
You're welcome to your opinion, I'm welcome to mine.
IQ is highly subjective. Requirement of stabilization is of less value with sports shooting, where you're usually at a very high shutter speed.
The Nikon has a much much deeper buffer and a better AF system (on paper for now). Those features may or may not be of use to you.
The lens system can be 'frozen' for a decade and still be more robust and fresher than what Ricoh is offering in K. Some of those long lenses are only a couple years old. There is still F mount on the roadmap though.
I also remember that time when a few people came over from Nikon for the K-3. Their reason wasn't because the K-3 was just that good, it was simply that Nikon was just that slow in launching the D500. I also remember most went right back to Nikon because the K-3 wasn't close to a D500 replacement.
Pentax lacks a lot of long lenses too. The K-3 III is a nice step in the right direction, but it isn't the only step they need to take if they want to capture the DSLR sport and wildlife community. Right now many are on a honeymoon phase with this new camera.