Why cels from Hey Arnold and other late 90s Nicktoons are rare

If you are a collector of cartoon cels, you may have noticed how it's relatively easy to get your hands on a cel from early 90s Nick shows (such as Rugrats, Ren & Stimpy, Doug, and Rocko's Modern Life), but not so much from shows from the late 90s (Hey Arnold, Wild Thornberrys, CatDog, Angry Beavers). The exception to this is SpongeBob. (Personal theory was that its sleeper hit status had something to do with it, but I'll probably just need to ask somebody.)

I have only been a collector for a couple of years, but I know Hey Arnold cels are rare and typically go for $300, and I've only seen less than a handful put up. Hey Arnold, I'd argue more than others from the late 90s, is more fondly remembered, for its large likable cast and memorable episodes such as "Pigeon Man" and "Arnold's Christmas". So when people see one, they bid high.

I'd spoken to someone last year who was working with the old Nick cel archives at the studio in Burbank, in preparation for the upcoming TV movies. The person said that the studio no longer had a desire to release these cels into the market, and chose to toss them after archiving them digitally. I can understand that they want the art to remain internal. That is likely what happened in the late 90s.