1) Patents in software tend to be granted for trivial, non novel solutions that any competent engineer with a few minutes or hours to think about the problem will emerge.
2) Innovations in software and hardware engineering are much more difficult to reverse engineer making them more stable when subject to attempts to copy. Reverse engineering much of software code (algorithms) is rendered impossible depending on how the code is implemented or made available for end use. The innovation is in the secret of the algorithm(s) which is locked in the implementation, as long as that is kept away from prying eyes it is a *defacto patent*. Reverse engineering such tech. is either very hard or impossible (especially for web services) so again lessening the need for formal patents in the space.
3) Once granted a trivial patent is like a hammer that prevent others from right to apply trivial methods and forces money into licensing deals instead of paying for more *innovation* in the form of R&D on new products and services.
4) Once granted and later defended or used to defend, large bulks of money go to lawyers...who in no way contribute to building innovation which can change human lives, it's wasted *human* investment.
5) In industries were patents don't apply there is rampant innovation (take fashion) and no shortage of competition or players willing to invest time to create new ideas (in clothing) ...if something is copied fine, they just innovate some thing new for the next season. We need that type of rapacious innovation to take hold in technology, and eliminating patents in the space (to some ironically) would do that.
Ted talk on fashion and innovation by Johanna Blakely