Absolutely, for most people it should be that way. (They might just need some education or some "herding"? to reach the solution.)

For developers, however, this would require Xcode to run well on iPhone chips too. With debugger, simulators and profiling too. Until the time this could happen, who knows what chips could larger devices include, and how devenv software might have evolved, so it could still feel like a compromise to run things on a small device like a phone…

Other type of professionals might have similar concerns.

And as you've mentioned Glasses, about four years ago I've said I was dreaming about developing for Hololens on a Hololens. Now, as Microsoft seems to have underperformed, that would sligthly change to developing on Glasses for Glasses. (Or, if experiments eventually succeeds: on brain for the brain?) 🙃

But we need to distinguish between dreams, rumors, and (short-term) reality.

I’ve also used to dream about unifying development platforms, for example, only to later reach the conclusion that multi-platform will almost always win; simply due to the fact that cross-platform frameworks will always have side effects, and more pragmatic programmers can still live — even without DRY-ing out everything.