For the record, I'm not saying that parodies themselves are declining in quality — far from it. If anything, they've just been getting better and better. No, what I mean is that advertising agencies and record labels are trying to put an end to parodies by claiming that obvious parodies (like the parody of a Lady Gaga song and the parody of a lobbying group's political ad, both covered on TechDirt here and here) don't qualify as parodies because they use the original soundtrack/video footage, meaning that they violate the restrictions on derivative works.
I think it's ridiculous that these companies are claiming that these parodies aren't actually parodies out of a misplaced fear that the original won't get views/sales. I guess that's OK for the ad company, considering that a parody video with the exact opposite message probably won't push people towards seeing the original ad, but in the case of songs, that is exactly what happens. Just look at Weird Al: often, his parody of another somewhat less-well known artist propels that artist to stardom. Plus, artists parodied by Weird Al consider it a badge of honor; for example, rapper Chamillionaire once said that his favorite song (as listed on his MySpace page) above his own song "Ridin'" was Weird Al's parody of it ("White and Nerdy"). I understand how poorly-done parodies can turn some people off from hearing the original version of a song, but as far as I know, the person who did the parody of a Lady Gaga song (among others) did these parodies quite well, so I can only imagine that many viewers who wouldn't have considered purchasing Lady Gaga's music started to do so after watching the parody.
So, media industries, why are you shooting yourselves in the foot by trying to stop parodies? The art of the parody is older than the music industry itself, so it's not even like these industries are resisting some sort of "scary new change".