I've used everything from half-frame to 10x8. I've been through the 'can't take the photo if you don't have a camera in your pocket' stage, all the way to 'if high quality is good then higher quality is better'. The compromises and trade-offs you make will sit most comfortably in different places for different users. I've been through two great thinnings of my herd of cameras, intending at my most severe to reduce them to an F6 and a Hasselblad. The buyers didn't co-operate and I still have a 4x5 and some half-frames, along with some 35mm bodies. Turns out I'm pleased that I do, as I'm currently having all sorts of fun with the Olympus Pen cameras and the OM-2ns, and the F6 is still jaw-droppingly good at its job. But though it all, I have become quite complacent about using an external meter or a cable release, and I'm not the least scared by tripods, even big and heavy ones.
So while I still like and enjoy variety, the single compromise camera I could live with alone would be a 6x6 Hasselblad. I can walk with it and use it hand held. I can stick it on a tripod and use long exposures with quality approaching 4x5. I can change lenses and viewfinders, and use extension tubes. I guess I've got to the point where a quick snap can be something from a phone, or maybe a supertelephoto wildlife shot can be done with the D850. But if I'm making a film photo (and I don't claim special skills at that, just that I enjoy it!), the Hasselblad is the comfortable tool for me.