No, i don't think so. If you make a pro-DX-body you go all the way or not do it.
It has to last for three years and the competition may outclass you otherwise a moment from now.
I suspect Nikon thinks that not every pro having a D4(s) is willing/capable to upgrade to the D5 but maybe will be tempted to buy the d500.
I agree.
Nikon has made a habit of making serious advents that stand the test of time.
I have been a Canon 7D shooter since I started, and I have been waiting for
something to come out from Canon that appeared to be the "perfect" successor to upgrade to.
The 7DII was founded on an outdated sensor, and despite all its strengths, at the end of the day it was founded on an outdated sensor.
I have been mulling the 5DSr, but wanted 4K. (There was no reason to omit 4K, but Canon did.) I even considered the Samsung, for their 4K, but it (and others like it) were too limited.
The Nikon D500 has (literally)
everything I wanted to see in a DSLR for nature photography. (Articulating/touch screen, high ISO capability, 4K, low noise, etc.)
There simply is
no limitation to the D500 (like there is the Samsungs, etc.).
It is not very convenient to have to sell lenses, switch mounts, etc.
But that is exactly what I will be doing by this spring ...
Jack