You'd have to ask why some of them want whatever full frame performance is to them. How heigh do you need the ISO to give acceptable files? How fast do you need the AF to be? Is it most of the time these shooters are just not really understanding the light, composition and camera as one?
Is really what they want a point and shoot, with Automatic flash/focus and scene choosing. I'm joking here but it's bedded in the reality of what's driving modern tech: faster auto features. Really learning how and why to use a setting on the camera would be a good point for anyone to keep at between shoots. If I can post un-edited images up here at shot at 12800ISO showing loads of detail and colour (raw) surely it says that a little crop sensor camera pulls it's weight there and anyone else can do the same, do you not agree?
This I need full frame thing, I simply have no time for it. You don't need it, you don't shoot medium format with f/2 lenses, or 135mm @ f/0.95
Pop or 3D effect has little to nothing to do with what aperture is used, it about lighting and composition. Nothing else matters, nothing. Available light that is interesting is all about, if you are shooting an event and don't like the light change it up, if you can't then get creative. IF you are shooting for a client stop the show and direct, that's what you are being paid for, if you're not then they might as well have gone and hired your uncle Bob as he probably has better & more pro looking gear than you, right? If all someone wants is a few snaps then they will be happy with that. Stop running around chasing gear thinking it will make your photography shine it won't. Only going out and learning will, learn to use whatever light is available to you, make it interesting and set the composition, CLICK. You're done.
GFX 100s with PDAF and 4K video though, mmmmmm... shame the sensor is so small. I hoped they might somehow have gotten the 54.3x40mm one to work and be cost effective, oh how I wished
I'm still on the fence with the GFX, I mean I like the camera and its nice to shoot with but so is the other X cameras. I just can't make space for it in my work or my personal stuff, but still medium format in that size at that price has a lot of draw all the same.