Well I don't agree with you at all. This statement is totally incorrect:
"Since the success of an upgrade is directly proportional to the quality of the pre-existing installation"
The success of an upgrade is entirely dependent upon the quality of the written software and the testing process it went through prior to release.
In the case of Windows 10 Ver 1803 - it is by far the worse of them all to date.
I even completely installed from scratch (ie nothing extra, clean HDD) Version 1709 of Windows 10 Pro. Perfect Installation no problems, everything correct. Then allowed the failure of ver 1803 to automatically update. It can't even boot! Even a clean install from scratch (clean HDD) does not even get to the asking to select keyboard, etc.
So Microsoft in it's pathetic attempt to upgrade have changed the most basic early install environment that worked in 1709 and ruined it for 1803.
My main PC for work is now back to Windows 7, that works perfectly. And this computer is going to form the start of my transition away from Microsoft to Linux. Windows 10 is proving to be poorly developed and lacks the thorough testing process prior to release. My Microsoft phone is also going to the dump as well. The Windows 10 Mobile updates to that have resulted in the same process of more failures and OS crashes than the very first OS it came with.
Upgrades should not be mandatory. Everyone, no matter whether it is Home or Pro, should retain the ability to tell Microsoft they don't want an update which causes their PC to fail.