I would think the camera body engineers (software & electronic) are largerly different group than the lens engineers (optics) with the sensor enginners having to have both. The mechanical group are now focused ( pun) on stabilization of the system... probably a restask of the shutter folks. Kind of interesesting overlaps came to mind as I wrote this comment.
I have been shooting BIF with a friend who has a sony a1 and pretty much an unlimited budget... He gave me the heads up on the red dot sight for bif.
We where both chuckling that canon has a $1000 f11 800. And the next step is $20000 for f 5.6. 2 stops is $19000.
If the nikon 600 6.3 is really good, that white space (pun) is really an big hole in product offering.
As to the mark up of the tc adapter when 'built in'.... yea that is obnoxious as the lens tc combo is cheaper and more flexible than the higher priced 'built in' it would be one thing if it could be flipped out of the way. A true lack of thought on that one. The R5 doesnt weigh enough to put much stress on the tc/adapter stack.
I find my CF varizoom crows foot mono pod to be a net strength/maneuverability advantage. Either shooting from simgle or slow walk locations taking all the load off is darn handy. The friction settings on all the moving parts keep the swings under control when this birds come blasting past.
Took awhile to learn how to dance with it, I am no Fred Astair (sp?)
I dont use it as a still tripod or leave it un handed for more than a few seconds, once balanced the effort to keep it aligned/standing is minimal