One major problem with the patent system is that one can get a patent on an idea that is not 'obviously' going to be useful because the necessary technologies don't exist yet. Because the usefulness of the idea wasn't obvious at the time of the patent, it's considered valid. Even if the invention in question would be an obvious application of the technology once it's developed, that doesn't erode the validity of the patent.
Further, part of the idea of the patent system is supposed to be to encourage people to develop new and varied approaches to doing things. Some patents are so overly broad as to basically encompas entire fields of endeavor and preclude anything else.
For example, Ralph Baer got some patents for video game devices. He did much original work on the subject, and deserved some patents for it. He attempted, however, to enforce his patents against all devices which move player-controlled objects around a television screen and have them interact when they hit. IMHO, that's going too far.
I would say that some of Ralph Baer's patents were definitely infringed, and would say he should have been within his rights to demand payment from anyone whose machine detected object collisions based upon whether two or more objects were "displayed" simultaneously (the time the electron beam was turned on to show the first overlapped with the time to show the second). Using 1970's technology, it would have been bothersome to do collision detection by other means (e.g. value comparison on position registers or level comparison on position control volages), but companies should have had the right to do so without having to pay royalties to Mr. Baer.
Thanks for the analysis. I know very little about the subject of patents, but it sounds like you do.