Hi jmk,
as far as I understand the default libs from KiCad located in the program directory should not be altered.
They are a wealth of data to start projects with.
When I move from V7 to V8 and on I would expect to have KiCad point directly to the Read Only Libraries that come with the current installation. Unless for some strange reason I would not want to update to the latest libs. (I guess this makes sense when I am using a nightly snapshot and do not want to bloat my hdd with several versions of the default lib installed).
If you update from V7 to V8 your local settings folder will have the correct paths to all your libraries.
My proposal was to ask the user: “I found previous (a) installtion(s) of KiCad. Please specify from which installation the settings should be copied”
Processing your previous sym/fp_lib_table should have links to all of your installed libraries. These have to be copied 1:1 to the new installation.
Again: If you are a pro you can always use a merge tool to determine which libraries you want to use. But I think beginners will be destracted and unable to cope with the current dialog window.
Best regards
Jan