The problem is that the mount is always a design constraint. The LTM mount means your lenses cannot have AF. The M4/3 mount means that your sensor size is maxed out at 1/4 the size of a full frame camera. Using the Pentax K mount means that you can't ever have a piece of glass closer than 45mm to the imaging surface.
The most interesting manuever might be Nikon's new Z mount which has the closest flange distance of any full frame mount as well as the widest diameter. This makes it so that it is compatible with the largest amount of lenses of any mount when using adapters. Bizarrely, I can use old Canon EF mount lenses with new Nikon cameras with more features than I can using old Nikon lenses from the same era!
Yeah but this argument is the same as saying that it makes no sense to standardize on USB-C for chargers because requirements can change.
The problem is that the mount is always a design constraint. The LTM mount means your lenses cannot have AF. The M4/3 mount means that your sensor size is maxed out at 1/4 the size of a full frame camera. Using the Pentax K mount means that you can't ever have a piece of glass closer than 45mm to the imaging surface.
The most interesting maneuver might be Nikon's new Z mount which has the closest flange distance of any full frame mount as well as the widest diameter. This makes it so that it is compatible with the largest amount of lenses of any mount when using adapters. Bizarrely, I can use old Canon EF mount lenses with new Nikon cameras with more features than I can using old Nikon lenses from the same era!
Sadly, this is entirely by design. Like other industries, camera manufacturers want to ensure lock-in. At least we can usually keep lenses across body changes within the same brand.