My, purely speculation, take on it:
They‘re behind production for the new iPhones and thus couldn‘t reveal them at the conference. That means that the GM they shipped there (which was determined to be the beta 8 build by them), had to be ready in time for the new Watches shipping today.
If you can‘t or don‘t want to leak your new devices early, the 14.0 GM can‘t tell us anything about the new devices (hardware features etc).
That‘s why they‘ll probably ship with 14.1, which potentially had to be finalized already so they could get them produced in time for their release in Oct/Nov or a potential reveal event in a few weeks.
14.2 comes after that, sure, but probably lacks the usual traces you have for new devices. It‘s not unusual that a point release beta (or even major release) lacks functionality / content the previous release had (e.g. the bugfree News+ Audio stuff in 14 or the exposure notifications system cause they were working on a new one behind the scenes).
My theory would also mean that we wont see 14.2 any time soon, because they can‘t release it before the 14.1, which probably hits around the time the first new iPhones are presented or hit hands. Once that happens, they merge the new devices specific things into 14.2, which could also explain why this beta has more woes than the GM, and release 14.1 for all other devices as a full release without beta testing.
That or they just went through major kernel updates in 2 weeks and skip 14.1 alltogether.
/redpill out