I don't like it either, because as you say it locks up useful tech. But I'm not sure it's any more rent seeking than private research. Purdue is public yes, but in most states even public universities receive much less than 50% of their funding from state and federal sources.

I still believe in some of the benefits of patents too though. What I'd like to see are compulsory licensing rules w/ ceilings imposed on the fees. And some sort of "public good" exemption for things like this that limit patent length even further.