Well, yes, of course. Everything is obvious in hindsight.
The intermittent wiper patent in question was filed some time in the 1950s, I believe. And it wasn't just the fact that the wipers were intermittent but that the mechanical approach at the time was heavy, complex, and expensive -- many moving parts. The famous inventor used electronics to bring the cost down to less than 10% of the "prior art" of the day, if I remember my inventor lore correctly.
So, in the 1950s, you couldn't simply order an electronic timer from Radio Shack, and especially not one that could be started and sensed by an electric wiper motor controller. In other words, your hypothetical description would not have been enabling in the 1950s.
As for cellular phones, my history is a little sketchy on the topic, but I remember phones in limosines decades before the cellular phone. The thing that makes a phone "cellular" isn't so much the phone itself but the network of base station "cells" and the use of hand-offs as you move away from one cell and into another and frequency hopping to find better signals and make room for others as they hop in and out of cells. And all those things involve the base stations issuing commands to your phone while you're talking. My guess is that the coordination of multiple base stations and the base station control of the operating paramaters of the "mobile units", i.e., phones, was non-obvious at the time.
My guess is that your hypothetical description of cellular phones would not have been novel in 1950 (or even earlier) -- except for making it the size of a tampon. I don't think tampons existed then, so you'd have an enablement issue as well. Speaking of enablement, I don't think you could have assembled the components you described into that size at that time -- at least not without the invention of the transistor. The IC might be a requisite technology as well, but you didn't describe that either.
The bottom line is that the description has to be enabling at the time of filing of the application. Your hypothetical examples are obvious now but probably weren't at the time patent applications were filed on those technologies.
I hope that helps clarify things.