"But inevitably, there are a handful of users who experience difficulty during the upgrade. This is due to the millions of configurations that exist and the complexity of making a product like Windows 10 work on the vast majority of them."
Bravo to that author!! There is no way that the engineers at Microsoft (nor elsewhere) can account for all of the possible configurations that any new update of Windows 10 (or even patches) will land on.
This is one of the reasons I, personally, think that Microsoft was brilliant in creating the Windows Insider program. It's just not possible to come anywhere close to having all possible configurations in-house as part of one's test bed. But if you can get willing volunteers to be your beta testers, who actually enjoy doing it, and who have an untold number of different configurations not available in house and where "real world" tweaking will have occurred your covering a lot more bases than you ever could by going at testing and QA in the way it's traditionally been done.
That doesn't excuse some of the stuff that's being seen, but it does excuse others. No one can be "all seeing" anymore, particularly not any OS maker. There's just too much hardware of too many eras out there where people are installing OSes that were never intended by their designers to land on that hardware. What's amazing is that it often works (for some value of works, but often that's "just works") even though it was never intended to.
Brian AKA Bri the Tech Guy (website in my user profile) - Windows 10 Home, 64-Bit, Version 1803, Build 17134
Memory is a crazy woman that hoards rags and throws away food.
~ Austin O'Malley