And many that weren't. Multiple automatically selected suspended parallax-compensated brightline frames, for a start. And a bigger lens throat with a simpler single mount. And...
Cheers,
R.
mm...bayonet mounting lenses, check.
viewfinder/rangefinder combined, check.
longer rangefinder base, check.
single non rotating shutter, check.
built in lightmeter (for the III model), check.
And all this happened almost 20 years before the M3, that didn't invent anything but incorporated all these important features (more important thant the parallax compensation already offered by Zeiss' multifinder turret and the automatically selecting grid that was never used by Leica after the M3, as far as I remember) in a Leica format.
The moral of the fable is not that the Contax was the best rangefinder ever, but that until the 60s there were many RFs built by many companies and some of them were quite remarkable (Contax, M3, Leningrad, Canon 7, Nikon SP etc...).
Of all these models just the Leica survived merely for fashion reasons and after the transformation of what used to be one of the best camera makers in a luxury brand.
All of this IMO, of course.