tcs is right - patents encourage innovation in the sense that companies must continue to evolve if they want to survive. There will always be less creative types who lag behind and pick up the pieces while the truly brilliant move on to greater things. We as consumers can only win with more competition and innovation on the marketplace.
I'm not sure why smallwheeler is so annoyed about this. Why is he worried about the "poor" Brompton owners that will lose out because their bike dropped in value a little more?
Bromptons has have many years to enjoy the fruits of their labor - and deservedly so. They've probably made tens/hundreds of millions from it, but the general lack of competition has let them keep the price out of the reach of the vast majority of cyclists. IMO many, MANY more people deserve to enjoy (and build upon) such amazing ideas.