Patents protect the little guy from the manufacturers.
A patent is supposed to secure the effort of R&D without necessarily having the budget for massive manufacturing. It prevents the manufacturer from taking off with your idea and giving you nothing for it. It seperates the manufacturing cost and r&d cost.
In software, there is 0 manufacturing, it is entirely R&D. As soon as you have developed your product, its ready. Hence why patents feel so useless in software.
Also why software startups are so attractive to investors.