Most people that do real R&D do it because they want to, not because they're rewarded with patents. They want to make a better camera, a better camera format, and sell it. And nobody learns how to make something by reading the patents, in the past 50+ years they're practically unreadable legalese. Once upon a time they had diagrams for mechanical devices or chemical processes, but now they're just ideas that many people faced with similar challenges and available technologies would have considered, except the first to bother to patent a general idea like "compress raw sensor data before debayering" now gets to be a massive pain in the ass to people actually doing R&D to make things.