What Happens When Patents Expire

After 20 years, anyone may practice the invention: aspirin, zippers, and jet engines are all open now. Generic drugs are the clearest case: patent cliffs drop prices 80 percent within a year.

But chemistry firms evergreen with new formulations, and phone makers layer thousands of active patents into FRAND licensing stacks. Copyright lasts far longer, trademarks can be renewed forever, but patents deliberately die.

Every technology you use without thinking was once a monopoly: expiry is where innovation becomes infrastructure..