During the Mac Pro redesign, Apple said developers are by far their largest group of "pro" users. Then they built a $6000+ workstation (with a $6000+ display) that appears to be primarily aimed at video editors. I don't see why adding some real programmability to iOS would be too niche.
I think the more likely answer is that Apple is suffering from tunnel vision in their conception of what "software development" means.
It looks like a great machine for developing software (if you can afford it) but all of its strengths as a development machine look like simply side effects of video editing machines needing lots of power. There is no design or feature on it that I can point to and say "this was done for developers". There are many that were obviously done for video -- like a $2000 FPGA option that's only good for 2 intermediate video codecs.
†Not that they'll actually ever say "I'm sorry" out loud, but it's pretty clear they're rolling back some of the late stage Ive-isms. Yes, I know they kept the Touch Bar and didn't add ports, but I think they're all fully committed to USB-C as the Way Of The Future™ and, uh, somebody high up loves that damn Touch Bar.
Without a reasonably performant platform to develop on the iPad will kill itself.
Besides that, why do you think that the current ARM chips aren't already faster than most x86 chips that people use?
Would be nice if Apple opened it up for trivial scripting though.
You can already do that using Shortcuts and various third party apps..
https://apps.apple.com/us/app/scriptable/id1405459188