Leica T series is probably pretty close to what they would come up with tho. Solid block of metal, and nothing but screen on the back.
I'm pretty sure that the major difference between a pro and a consumer camera is the amount of easily accessible buttons and knobs.
Precisely this. After 10K shots on a Canon 1200D, I upgraded to an 80D specifically to have access to the top controls to quickly change settings while shooting. You can remap a lot of the 1200D's controls in the "Expert Feature"/customizations section, but the 80D's extra ergonomics are a true joy. The camera is molded to my hands and comfortable to wield for hours at a time.
I can't say the same for the smartphones I shoot with. My Blackberry KeyOne's camera has fully manual controls (even the focus distance can be manually set!), but the "slide your finger to control settings" UI sometimes feels like the "Reddit designs volume control" experiment from a few years ago. I empathize with the Java programmers, but it's extremely frustrating to tell the smartphone what kind of picture I want. It should go without saying that it's equally frustrating to be unable to hold the slab phone adequately still.
Reading people's passionate hatred for real cameras makes it quite clear that they aren't the target audience for a simple mid-range DSLR, let alone monsters like the 1D or Nikon D5.
But they can make great physical buttons. That last iPhone home button was one of the best in the industry.
I bet Jony Ive and Phil Schiller love Leicas