It's data which shouldn't be bound to a specific computer, but rather reside on a NAS or something where it can be accessed from many computers (possibly with different operating systems). Your general approach looks like "I have just this one computer which runs Linux and I care about nothing else".
As per the above, putting a data collection not entirely tied to a specific OS or a specific computer into a specific user's home directory is not a good idea, it should be a separate data-only filesystem. Apart from that, do you put all ISOs together (no matter if Microsoft, Linux, BSD etc.)? Or rather put different things which all belong to a specific OS (ISOs, updates, drivers, program binaries/sources, documentation) together?
See above. There's much more to an OS than just its ISO image (look at mdgx.com/web to get an idea).
I'm not talking about installed drivers, but about archived driver installation packages. Do you group drivers primarily by hardware, or by OS, or yet differently? Do you keep them with OS-related files (see above), or rather with hardware-related files, or separately?
Not everyone wants to keep redowloading software over and over again and be at the complete mercy of a package manager, internet connection and online repository.
It's not really that trivial, partly for reasons cited above, and partly because it might be more convenient to store docs/books/videos etc. together with other files on the specific *subject* they concern.
The web in not eternal and online archives like the wayback machine are not perfect. "a lot" is relative, but it's not a bad idea to archive websites (or parts of them) you consider of special value.
Not really, much rather it's about a much more general, OS-agnostic and machine-agnostic approach to organizing storage. Contrarily, your replies seem reek of Loonix fanboyism, and at the end of the day it's hard to take a fanboy seriously.