The US practice of patents helps incentivize inventors to study and innovate so that they see an ROI when they sell to a large company able to handle exploiting a defending a patent. If you wanna try to make a company on your own around your patent, you’re free to try but we don’t build the system around moonshot strategies that are likely to fail (i.e. making the company around your patent).

I’m not defending the system, I’m simply explaining. Likewise, forever copyrights exist to increase the value of artistry so that artists get something back when they sell them. Again, not defending.