The idea that software development is the sole province of the lone inventor is both wrong and irrelevant. The reason that our constitution facilitated patents was nothing to do with how many people invented something but rather with encouraging disclosure of the result.
If we stipulate that software patents are frequently violated...so what? Without further analysis of why or whether specific improvements to the system would be helpful this is a dangling factoid - no more.
Finally, the idea that copyright provides any kind of protection for software is so ludicrous the writer's naivety is laid bare. Copyright protects only the expression of an idea. In the case of a work of art such as a novel or painting the expression is critical to the work and copyright is a valuable protection. But if a programmer sits with original source code before him and rewrites it in another language thereby benefiting enormously from the original work but changing the expression completely they may indeed be programmers writing "their own code" but it certainly isn't "from scratch", and whilst he is right that "they can be confident they aren't infringing others" it is blindingly obvious that they have copied. Copyright is worthless if the expression doesn't matter and all that matters is functional equivalence. And guess what, users don't give a rat's ass how a program is expressed so long as it works.