Hah! typically it's the client and/or project parameters and budgets/deadlines that determine the choice of gear.
I try to shoot film as much as I can, especially in MF or LF but don't always have the budget or the schedule for that.
Also, in the studio, a lot of the clients want to pixel peep every shot, etc., so that's another set of gear to enable that to happen.
You're looking at a set of kit built up over 40 years' worth of studio and location work, though. And mostly, whenever I've told myself I'd lighten things up, finally, another gig comes along that has required that I get something else to do the job properly
And of course, you're right! My MF and LF gear needs refreshing... ha!
Actually IMO it's the Bayering that screws things up for digital cameras in general.
Especially in the studio, with table tops, product shots etc, that are usually LF and lit slowly anyway. If one takes a decent drum scan off a LF or even MF tranny (or neg), there's really no catching up to those three RGB files by the deBayering processes available today. Trying to make digital match analog is, IMO, a waste of time, since the time spent trying to get a digital post program to undo all the problems the existing processes add to the image processing pipeline can be way better spent just sending the unprocessed stuff to the lab, getting the E6 or whatever done, then on to the drum scanner and files on a cloud and back. A little post tweak and done deal.
Of course, in this case, digital still has an essential role - it's replaced the Polaroid proofing system of yore.
So - set it up and light it up (same time as it always took)
Shoot as many digital proofs as the client can stand.
Once s/he selects a good one, shoot that in MF or LF.
While the art dept is monkeying around with the proof shot, the lab is processing and scanning the "real" shot.
Next day, or whenever (it's still quick in LA) the "real" shot gets re-introduced back into the final comps and voila - the client still wants tweaks, for days more, usually.
Way of the world, my friend.