More importantly, as the above quote notes, the really smart creators understand that if you create characters whom you care about, then the sexual content depicted with them is usually much more satisfying beyond mere titillation. That said, even today, there are porn films with intriguing if not all that well-developed plots, and at least some porn stars are serious albeit often not terribly talented actors. A more tolerant public, being in combination with the explosion of the internet allowing for easy distribution, the overwhelmingly Porn Without Plot porn world we have today, was not infringed.
In some cases, pornos were once made with plotlines so that they could be considered 'art' and thus protected from the laws against indecency. Bonus points if the sex is actually plausibly worked into said plot or used for characterization. As in, it has a plot that isn't merely an excuse for having sex on screen. Any porno where the sexual stuff is not the only point to it.
