Your explanation of the ease of installing Windows 7 on a PC with XP is a fine example of what this article is saying rather than rebutting it.
If a person needs an external drive for backup isn’t that a PC tax? You don’t need it for a Mac.
If a novice or non-technical person owned a PC and wanted to do the upgrade as you describe wouldn’t they need someone to help? Most have no idea what partitioning a drive even means. Aren’t they likely to have to pay for the help? Isn’t that a PC tax? It is not necessary on a Mac, unless of course you are doing the MS OS upgrade on a Mac.
As soon as someone buys a non-partitioned Win7 computer he should partition it. This can be done via control panel >>>
to admin tools>>>
computer management>>
disk management>>> then create a storage partition
Vista had the above tools too
One this is done you don’t need an external hard drive when you want to re-format or upgrade from Vista to Win7 OS.
Plus I remember seeing Swordmaker advising APPLE users to backup files before upgrading OS or installing new OS. That means you guys been an external hard drive too.... Unless Apples come with a storage partition already