With the rise of creative commons, or should we say the "maker" commons, the need for patents is greatly reduced. Whatever remains is probably best served by mega-Kickstarter-style bounties funded by governments or ultra-rich philanthropists, large-scale moon-shot or Manhattan-type projects for finding the cure for cancer/aids or the elusive quest for sustained nuclear fusion.
Think of it this way. In an island with one inventor, you damn well should treat that inventor like a king if you want to live better than flint-using troglodytes. But where there are potentially hundreds of millions of inventors working on their own small design, awarding one big patent for minor design improvements become counter-productive. The patent will actually stifle attempts to evolve the technology independently.
History is actually full of examples of similar technology being independently developed by different people and even different cultures at different places and different times (things like the printing press or the gun or even intellectual "inventions" like calculus and the theory evolution). True, hundreds of years might pass before something is reinvented. But when even plans for how to build a gun can be posted online, an invention can be improved by hobbyists tinkering with a design known to work (no reinventing the wheel).