Sadly, I've noticed that QS scenes are far fewer, both in movies and in cartoons. Yet even at the 'peak' of QS perils, too many times, the 'quicksand' was nothing more than water with either leaves or sawdust on top, or just merely dirty water that he/she could easily swim out of.
However there was a scene in "Wreck It Ralph" that involved a quicksand-like scene with a female charachter and a male charachter that I thought was a great scene. I can't remember the details at this time but apparantly they were in some kind of candy-like kingdom and they were sinking in 'Nesquik Sand'. Let's just say that towards the end, I can't tell you all the EVIL thoughts that ran through my head as I watched it.
So, in the end, I've noticed a sharp downward trend in QS scenes in media and Youtube is a notorious offender in deleting QS videos, but I still come upon some really good QS scenes once in a while.

Just watch "Wreck It Ralph" and you'll know what I mean.
So while I don't necessarily call it an 'extinction', I do this decline as also being part of increasing censorship by too many PC camps as I mentioned on a separate thread. Youtube not that long ago, took down numerous QS videos, many of them were animated CGI videos that I've found nowhere else. A few QS users here even unsubscribed from Youtube as a result of this.
Perhaps the only way for QS is now up but I definately sense a 'nadir' in qs scenes within the 'mass media' as of this writing.