Standardization is an entirely different argument. The point is that it’s unlikely that Apple wants to do away with the Terminal because it treats the Mac differently than it does its other devices.
I still don't agree with your point, then. Apple does treat the Mac just like their other devices, and they use it as the justification for sweeping API depreciation and user-hostile software decisions. If Apple made a decent way to develop apps entirely in Xcode, I wouldn't trust them to keep iTerm around for a second.
API deprecation on macOS is somewhat overblown. It’s not difficult to get a decades old FOSS Mac app compiling again, and it’s even possible to get projects targeting OS X precursors building with a little effort. Binary compatibility is what gets broken more frequently and is necessary to keep an OS from tripping on its own compatibility hacks.
Should macOS ever lose its terminal and associated capabilities, it’d spur mass migration of users from several STEM fields overnight. It’d be a colossally stupid move that’d destroy a sizable chunk of revenue coming from sales of high-margin and high-spec machines and services that these users buy to use with those machines.
Really it depends on perspective. The #1 reason I left MacOS after Mojave was the fact that none of the APIs I deployed to were naively available anymore. I had to buy a new computer to get updates for the same software I used before. I waited for Apple to reverse their stance, but it never happened.
It's entirely feasible that most people don't encounter the breakage or even notice it. Developers do though, and the breakage on MacOS is legitimately unprecedented. It's the most prominent example of API decay I've seen in a long time.
Xcode Cloud is the writing on the wall, don't say we didn't warn ye: https://developer.apple.com/xcode-cloud/