The Problem....
....With this first generation of smooth-top ranges was that they were more trouble to keep looking spiffy than a coil range, not less. The easy-clean promises were pretty much bogus.
The problem was the white color - it showed absolutely everything, and it would stain if not rigorously maintained with Corning Smooth-Top Cleaner and Delete powdered cleanser (very similar to Bar Keeper's Friend) for tough, burned-on spills. The smooth-top cleaner had, I believe, silicones in it to condition and seal the top's surface.
Added to that was the fact that truly flat-bottomed cookware was not easy or cheap to come by in the early '70s.
Today, flat bottoms are much easier to find, at a variety of price points. And the current generation of smooth-tops is black or dark grey, much less prone to showing imperfect maintenance.
My mother, who detested housekeeping, bought a '74 Lady Kenmore smooth-top because she believed in the easy-care promises. She did not keep it long, and she was not a lady who gave up on an appliance easily; she was appalled at the effort needed to keep it looking even reasonably clean, much less showroom new. I got it from her and used it quite a while, but eventually I also tired of the care requirement.