“After expiry, the only real issue left is usually compensation for infringements that took place before expiry. The expected back royalties or damages have to be very large before it can normally make business sense to sue over the historical usage.”

Despite the criticism of Brulotte and its conventional interpretation, the circuit courts will refuse to enforce royalty provisions that require continued payment of unreduced royalties on patents after expiration. What remains unsettled, however, is whether courts will uphold a royalty provision that calls for a reduced royalty after patent expiration. Because Aronson upheld a reduced royalty where no patent actually issued, it does not guarantee enforceability of a reduced royalty after patent expiration.