Animals (and CGI) are EXPENSIVE. A movie won't happen because no one would ever want to shell out the money for that questionable a success. Nah, if it ever gets touched again, it will be something much lower risk. I'm half-expecting a comic series, whey could do so much with that.
Yeah, I’ve been known to joke that That Fucking Hawk (aka the questionably-talented actor who played Tobias and presumably shat on Brooke Nevin an untold number of times) was personally responsible for driving the show off the air, because I have no idea how much of their minuscule budget AniTV blew on that stupid bird but it was probably a huge proportion. Honestly, I’ll never know why the show actually delayed restoring Tobias’s morphing power for so long compared to when the series did it, given that they did save themselves a lot of money (and a lot of narm) by having Visser Three and Ax pretty much always walk around in human morph, and could have done the same with Tobias as well.
Honestly I’d love to see an animated adaptation of Animorphs (I’m thinking something like Avatar meets Attack on Titan but with transformation sequences straight out of Akira) if I had my druthers, because that would eliminate the budget issues while also cutting down on the likelihood of whitewashing. There are also a lot of concepts that a live-action show would necessarily struggle HARD to be able to convey (I still cringe thinking about how AniTV shot Jake’s conversations with Temrash 114 while he was a controller) whereas there are lots of Anime and cartoons that successfully convey multiple characters inhabiting one body through various unreal animation schemes that get the point across. Anime also have a good history with conveying huge discrepancies between appearance and character (I’m thinking of how sweet and adorable Alphonse Elric always seems despite the animators only ever drawing a huge suit of armor), whereas live action adaptations continuously struggle to convey that pretty people can be evil and ugly people can be good (*cough* fans are still trying to redeem Loki post-genocide *cough*).