Since the royalty is exclusive it means that you are the only one that is allowed to profit from the patent and here comes the defendability of patents.
However if you really want to protect something then, by all means, keep it secret. Coca-Cola and Pepsi formulas are kept secret and will not be patented, for example.
Patents are no longer just used to protect the Widget. They are blurred into generalized legal bludgeons using the widget only as a pretext.
There have been oppressive regimes that distorted the existing legal framework to use as a pretext for oppressing dissent. There have been nations using various combinations of fact and lies as a pretext for going to war.
Laws are fine, but laws subverted to be used as a pretext are an abomination.
National sovereignty is fine as a foundation concept in international law, but deliberate distortions that use the protection of sovereignty as a false pretext for war are abominations.
Patents that truly respect prior art and are crafted to describe a specific mechanism are fine, but used as a vague and mushy pretext to enable large companies to arbitrarily bludgeon you with their legal department are an abomination.