The alternative isn't some utopian free sharing of inventions. The alternative is tightly held trade secrets and lots of inventions dying with their inventors.
We had this system for most of human history. It sucked. A decade and a half of exclusivity is a fair trade to avoid it.
Software patents maybe shouldn’t exist as it didn’t for a very long time. Indeed, the way patents are actually written for software ends up with a convoluted mess trying to remain as generic as possible to cover all possible extensions of a core idea (and you can’t patent ideas). So while patents show a benefit, it’s pretty clear the current system in the US has a lot of flaws that need attention.
We had this system for most of human history. It sucked. A decade and a half of exclusivity is a fair trade to avoid it.