Is there a way to copy all of the symbols and footprints from the read-only libraries into new ‘custom’ libraries, without having to do it one symbol or footprint at a time?
Mod. Edit: A new topic which deserves a new thread. 
In KiCad, a footprints library is just a directory, and each footprint is a separate file. So you can use your operating system to copy (parts of) a library to another place.
Do you really want to copy whole Kicad Libraries to Personal Libraries without any editing?
Copying a single footprint or symbol from a Kicad Library to a Personal Library is as simple as:
Right Mouse click the item,
Left click “save as”,
Highlight Personal library, then OK.
The only problem with this method is the scrolling, but that can be overcome by temporarily changing the prefix of both your,and the Kicad, library nicknames or “pinning” those libraries.
The libraries are arranged in numeric followed by alphabetic sequence according to their nicknames, so all you need to do to remove the scrolling is to eg. place a 1 in front of these two library nicknames and they will both then appear at the very top of the library list, hence the scrolling is eliminated.
This method is particularly useful for sorting the symbol library “Device” into more useful and easier to manage and access Personal Libraries such as Capacitors, Resistors, Transistors etc.
There are two very useful FAQs regarding this topic:
This one and this other one.