They never will be. You're not going to want to load 100GB of instruments, samples, etc., onto your iPad, burn out the battery in a few hours and ultimately expand the device by loading third party plugins like LiquidSonics Reverbs themselves range from 200MB to 100GB of Bricast IR samples in 44khz-96khz.
All these 3rd party vendors support VST2/VST3/AU/AAX and are just getting around to Silicon. Nearly all of them are not AU3 Audio Unit plugins. The few you see on the AppStore are stripped down plugins.
Most of the vendors have to support several DAWs and it is far simpler to focus on Macs than on iPadOS and macOS.
This isn't going to convince users of Pro Tools or Ableton Live, or Cubase to move to Logic Pro. And it isn't going to convince Mixing studios using Logic to add this to their arsenal. Small independent Instagram training mixologists like YouTube channels who barely scratch the surface or do nothing but sampled music and not actual analog mixing of Drums, Bass, Synths, Orchestral Strings, Brass, backup singers, etc., to Live performances will ever use these iPad products.
The notion Colorists are going to use FCP behind the director's chair on-set is far fetched. Colorists are post-production people. All of FCP is post production, not on-the-fly in production work.