Well hello monopoly, bye bye competitive prices.
Bingo.
A patent *IS* a monopoly.
It grants a legal monopoly for a limited time to forbid anyone from copying your intellectual property.
It costs a full disclosure of that intellectual property.
When a utility patent expires anyone, anywhere can make the exact same widget or use the exact same code. Your idea becomes the property of all of mankind.
The benefit of your creation outlives the patent, that brief period when only you can make or authorize the manufacture of your idea provides the incentive that drives innovation.
Why would anyone go through all that work if they could not profit from it?
The whole point of a patent is to establish a temporary monopoly, to provide profit in return for invention.