Kabuto: Why do porn parodies always have to be of the XXX variety? I have a relatively tame alice in wonderland softcore porn on my dvd shelf that came out in 1976 and is actually a musical. There's sex and nudity in it but the movie retains a light and innocent feel to it while keeping a good movie pace (vs hardcore where extended scenes destroy the pacing like the ill advised later home release of this movie featuring XXX inserts).
doccarnby: Hardcore is what's in right now. Uhm, no pun intended. In the '70's, there were cultural and, I believe, legal considerations that made softcore more appealing, as well as a feeling that anything can be art. Nowadays we've moved to excess in various forms and the idea that these are best for cash grabs, so it would make sense that our porn would focus more on the excess and, well, lack of artistry as well (not to say that these are necessarily bad, part of the fun of the porn parodies nowadays is that they're well made and have more to them than normal porn). Presumably, eventually our culture will become more prudish, or there will be an artistic porn renaissance, and softcore will come back into vogue.
The softcore industry went under because in the long run, their whole premise was flawed. Trying to make sex movies without actual sex isn't something that people are going to be interested in after the novelty wears off. And in case of softcore porn movies, the novelty wore off decades ago.
The current porn industry is almost exclusively focused on satisfying the demands of their paying customers, so going hardcore is the lofical choice for them.
Very, very few people are audacious enough to explore sex as a powerful tool in artistic storytelling (which means, use sex for more than the obligatory love scene to bring some passion into the plot). If you're interested in modern attempts to use sex artistically, google for "Destricted". It's a 2006 compilation of some shorts, but also an ongoing project IIRC. Don't approach it with high expectations though ... it certainly has its weaknesses.
That said, Marco Brambilla's "Sync" demonstrates the interchangeability of hardcore flics pretty well, imho.