I've yet to see a software patent which wouldn't have been reinvented by someone else looking at the same problem. The thing with software is that the cost to experiment is extremely low compared to other fields so we can, and do, "just try it".
At this point in my career for example everything I do is basically tweaking or adapting patterns I've seen in other systems to the ones I'm working on.
Cost to experiment being low doesn't make non-obvious ideas obvious. As a trained researcher with patents I'm no longer surprised by how often simple ideas have remained undiscovered for decades.
At this point in my career for example everything I do is basically tweaking or adapting patterns I've seen in other systems to the ones I'm working on.