I have the 35mm/2.5 color skopar and the old chrome 35/2.8 Serenar (Canon). I think the skopar is a "better" lens most of the time, but the Serenar still works very well.

Even in the 50s a slow wide angle was not horribly difficult to design or build, at least with the back focus of a rangefinder body. It was considerably harder to make a 35mm lens faster, and especially if it needed room for a flipping mirror.