Indeed, that's the point. Either you make your patent make money for you, or sell it. Otherwise, you let your exclusive rights go.

A ton of patented stuff is regularly reinvented by people. In many fields, key ideas are so well-understood by practitioners that who patents them first is mostly a game of chance.

There's no point to allow someone (usually a company that does nothing but sits on patents) to do nothing while blocking everyone else from independently reinventing and implementing it. It is especially spearheaded against companies which buy and then bury an idea to preserve their incumbent status for 25 years more.

A monopoly is a bad thing. Sometimes it's a lesser evil, but most often it's not.