You make the patents too easy to get and it fucks the little guy over as the big corps hoover up all the ideas. You make them difficult or impossible to get then that also benefits the big guys over the little guys as they will just steal people's ideas and produce them for cheaper with their existing infrastructure which creates an even bigger monopoly.

There is a sweet spot that society is trying to reach. It's imperfect like any system but it's far far better than having no system.

You've not even considered that in order to get a patent granted you have to disclose your invention to the public which stops big corporations hoarding too many trade secrets.

All in all, the idea that patents shouldn't exist benefits nobody except the large corporations. Say goodbye to start ups growing in size if that is the case.