Patents are a bureaucratic process to secure exclusivity on an idea, process, or product. Patents have a two fold official effect: they are meant to lower the risk of innovation by limiting competition. They are also public, which means that others can use them to learn and build upon them.
Some products are not patented exactly to keep them secret, especially because patents are granted for finite amounts of time.
Getting a patent is not a cheap process.
Patents are a tool to increase Technology Transfer, but also Patents can be used to block third parties. Therefore, one of my open questions is how to achieve a situation in which patents should not be a block for innovation.