Not true. In past, there were patented technologies (GIF, MP3) that were allowed to be used freely, until they got widespread. Then the lawyers started asking for the money. It was deliberate strategy, that would not work if the above would be true.
In Troxler Electronic Labs v. Pine Instrument Pine waited 5 years before suing, saying he didn't feel motivated to pursue the claim, and the judge found that insufficient reason. Symbol v. Lemelson found that the submarine patents were invalid due to laches.
It's easy to get lost in the law, though, so I'd love some specific citations that go the other way.
