People seem to feel young adult fantasy/dystopian is on its way out. I think young adult will still be relevant for a while, since it's the genre all ages seem to be up for reading. I don't know about the dystopian thing. I think it may be quiet at the moment, as so many of the novel series and subsequent movies on them have ended, but I don't know that everyone got sick of them and another popular one won't pop up.
That's a heck of a big genre to disappear.
1. YA isn't going anywhere as long as teens like to read about other teens, and people who used to be teens like to read about teens. The entire 14-19 age range isn't going to disappear (unless you're writing a particular YA sci/fi dystopia). In fact, the "coming of age" story, which deals with that basic age group, has been around for a really long time (Romeo and Juliet, anyone?)
2. Fantasy isn't disappearing. Again, with its twin sci-fi, it leaves authors with a great way to combine action/adventure with comments on today's world.
3. Dystopia may be a trope, but it does the basic job a genre does - it gives the protagonist a problem to deal with. If life is all sunshine and strawberry lip gloss, what will the hero or heroine have to do? In the face of today's current economic, political and ecological turmoil, stories that ask "If we took this trend to an extreme, what would life look like?" will still find a place, assuming they're well-written.
Now, such stories won't have the glossy newness factor they once did by putting all of these things together. But I'll wager there are a lot of unique takes on the genre still out there.