Its just we don't call them kitchen computers. We call them smartphones and tablets, and they're even more embedded in our lives than many of these 1970s futurists could even imagine.
And yet at the same time we're still nearly as far off from truly completely automating the kitchen. I still don't have a machine that I walk up to and it can make me a wide variety of meals with little to no interaction on my part.
Its still interesting though that it seems like in the 70's they were still expecting there would be some centralized computer in charge of it all while in reality computing got so small and so cheap its found its way to each appliance on its own.