Unfortunately, it is really more along these lines:
1) Apple releases a beta of the new OS
2) The people who write 3rd party software test against the OS, and if needed release a minor version upgrade
3) End user upgrades the minor version of their software automatically
4) When the OS is released all the tested* software is compatible.
* tested software includes a couple of the built in programs, usually excepting Mail and Finder, Adobe products not included.
5) Version X.0 delivered to great fanfare
6) Numerous issues discovered in X.0 within 48 hours, typically in Mail and Finder. Apple support servers spool up to include most of Amazon and Microsoft's cloud.
7) Three weeks later X.1 released
8) Within 48 hours, about half of the original complaints have been fixed, another crop of issues discovered, usually in Mail, Finder and Adobe products
9) Apple support servers again spooled up to utilize a significant fraction of California's electrical supply.
10) Three weeks later X.2 is released
11) Within 48 hours, about half of the original complaints have been fixed, another crop of issues discovered, usually in Mail, Finder and Adobe products
12) Apple support servers spool again, NASA determines that California has the hottest month on record.
13) Three weeks later X.3 is released
14) Most issues solved, Apple support servers go back to just requiring more power than most European countries.
15) X.3 - X.6 released to no fanfare
16) Some idiot at Apple has some weird, non standard way of doing something simple (Hello Airdrop), breaking compatibility with everything other than the very last round of hardware
17) The remaining tale is left as an exercise to the student.