It will take them a good deal of time and money to clean room reverse engineer a non-trivial algorithm. During that time you can profit from your invention, and advance your product. It will probably cost more money from them to clean room reverse-engineer your product than to just license it from you. Phoenix BIOS only happened because the code was small and the reward for interoperability so artificially large due to IBM's control. If the BIOS just did something useful (a) there would probably be academic papers on how it worked, or (b) other people would probably have just licensed it.