Oops. I don't know of anything that would have turned out for the worse without software patents. But I only know about a subset of uses of software. There might be cases in pharmaceuticals or manufacturing where patents helped protect individual inventors against big companies.
It seems pretty obvious that if instead of patent system we had a mandatory obligation to publish full specs (schematics and source code) for all marketed products the invention rate will grow exponentially. The development costs will be cut down because of possibility to incrementally improve on existing products.
