Combination Color and Contrast Control

[Tom9589]

I've noticed on a number of the early color TVs that the Color Intensity Control is often ganged with the Y Contrast Control. That makes sense since the greater color, the greater the Y contrast needs to be.

Why was this design stopped? Was is like DC restoration in that the average customer couldn't tell the difference? Was it the cost? Was it both? (Was Muntz lurking in the shadows?)