There is a statute of limitations on Patents.
But that isn't what was said. Yes, there is a current 20+6 expiration for patents, but the statement was 'if they aren't used' they expire, assuming the writer was meaning
earlier.
There appears to be no mechanism that would 'expire' a patent if it's not used.
So a company can buy a patent, and sit on it, like a spider, or a snake, and wait until someone puts something out that is
remotely like their patent, and 'throw the spaghetti on the wall[/i] and see if they luck out and get a sympathetic court.
There was a recent case where the court, on appeal, ruled that the original court erred in deciding for the patent holder because the patent did not cover the actions of the infringer. The patent holder has nothing to worry about. If they lose, they pay their costs. If they win, or are able to force the alleged infringer to settle, well, they win...
MANY smaller companies have been forced to settle outrageous suits based on them not having the capital to fight the case. Considering that these cases can, and often do, last for tens of years, and the costs involved of searching for prior work, and other avenues, they are very costly for the accused.
That's why, IMO, software should never have been allowed to be patented. Period.