Five years and several million cars later, Kearns jumps out of the bushes and whacks you in the kneecap with a lawsuit. What should your penalty be? Do you agree with the judge that you owe some guy $10,000,000 for a trivial idea that he happened to have before you did?
That said, Its not about how simple or how hard an idea is right? Its about how much value it adds.
EDIT: In your example, as long as it is not willful infringement and as long as he started making them before he patented it, there will not be any penalty. But in case of ford and Chrysler, its willful infringement.
If the plaintiff can show that you did know about the patent and infringe it willfully, the damages are tripled.
[Kearns] first patent for the [intermittent wipers] was filed on December 1, 1964. http://en.wikipedia.org/wiki/Robert_Kearns
The 555 timer, however, was designed and invented by Hans R. Camenzind ... in 1970 and introduced in 1971 by Signetics http://en.wikipedia.org/wiki/555_timer_IC
The 555 didn't exist when he invented his wipers. What is your solution now?
Given almost any mechanical or electrical technology, there exists means of using that technology to control the duty cycles of machines. The 555 was just an example of what you might use to implement an intermittent wiper.
As I understand it, accessories like windshield wipers originally operated from manifold vacuum, so the patent probably describes some sort of vacuum-based contraption which would be as obvious to MEs as a timer circuit is to EEs.
Another point being, even if it were a novel concept when implemented with vacuum lines and valves, it certainly wouldn't be novel or unexpected when cheap solid-state electronics did arrive on the scene. But chances were good that the patent claims were broad enough to hold sway over future implementations. (Disclaimer: I haven't read it.)
So fast-forward your 8-track to the early 70s: windshield wipers are now run from the car's electrical system, and wow, hey, cool, here's the 555... and meanwhile the goofy patent's still in force.