Is my recall correct about Windows writing to them [libraries]
instead of leaving them as 'original' ??

I never quite understood why some other OS's were able to use static
libraries for such basics as accessing the hard-drive, or other
standard OS operations. While Windows insists upon customizing it's
dynamic libraries through programs modifying the libraries.

In both approaches, all programs share the libraries. But with static
libraries, they don't have to attach to them or modify them, to use
them. The programs just call for, and use the OS standard libraries
to interface with the computer hardware. Otherwise, the program does
what it must, manipulating data within its program; then calls for
the use of the printer through the printer library, or whatever
hardware it needs to use to get the results on the screen or out of
the computer in some manner.

The program wants to print, the OS says this is the printer to use,
here are the drivers to use, here is the port you will print through,
use the print library, send the data....... The program doesn't have
to attach to a static library at all, nor use a registry of where one
is; just send through it in the central library directory. This is
why you can re-locate a Mac or an Amiga program to another directory
or drive and it still continues to work.

Am I mistaken?