Not really on topic, but is it possible to acquire a 'defensive' patent? Maybe by placing a patent into public domain or otherwise promise through some legal means not to pursue legal action against anyone who would like to use the patent?
In the novel Accelerando by Charles Stross one of the main characters creates hundreds of patents and sends them to an organisation which had as it's mandate, a responsibility to grant licences to any patents in its portfolio for free. A similar org would be awesome.
Sure, you could acquire a patent and cease paying maintenance fees, or place it under a very broad license or covenant.