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.
I used a word processor on the C64. Spreadsheet software. Paint programs. Vector graphics editors. Ran a BBS, nightly sending email all around the world via Punternet(like fidonet), shared files, ebooks, etc, etc.
While there is more processing power today, outside of a web browser, maybe 70% of the stuff I do on a desktop has not improved with modern computing post 80s.