Voyage of the Little Mermaid is fairly new, and is already regularly a walk-on.
Mission Space had insane waits when it first opened.
Ditto Expedition Everest.
I have seen sad piles of unsold Anna and Elsa costumes post-Halloween, when the rest of the costumes were long gone from Target! Frozen is yesterday's annoying cliché. The repetition of Let it go, let it go, let it go, doesn't thrill kids. It makes them cringe.
I'm sure there are Disney fans- especially adults (and parents who don't know Frozen is now OUT)- who will flock to experience the NEWEST WDW attraction for 4-6months. After that, not so much. It wont be popular again until today's newborn's discover it. (See, "Potter, Harry".)
We should not assume the new loading will be the same as the old. I trust WDW's fine engineers studied improvements. Unlike Dumbo, BOAT rides have a tremendous ability to modify capacity as demand warrants! Just add/remove boats. I'm not dismissing the possibility that CM's will MANAGE Frozen so that it appears full.
For a whole year, the
Disney store didn't carry Frozen merchandise! That fed the craze, but also a sour taste. Kids moved on, but they haven't forgotten the frustration they felt.