When statutory IP rights expire, their subject matter (the patented invention, for example, and the copyrighted song) is all thereupon injected into the public domain and thenceforth freely available for all to make, use, sell, reproduce, modify, mashup, and mutilate.  The American public, having permitted the IP rights holder her “limited time” of exclusive dominion over the thing, finally gets the thing back.  It may take a long time — over a century in some cases — but, except for brands in continuous use and secrets kept continuously secret, the public domain chickens always, eventually, come home to roost.

I am surprised some enterprising Lessigite has not yet built a machine to review relevant public filing data and do the math to ascertain which IP rights expire each day and report on it, perhaps in targeted fields.