In order to contain costs and comply with licensing agreements, the Library must promise that access to the content is tightly controlled.
If if a sponsored NetID gets reactivated (yearly, say), this is in and of itself insufficient for library resources. A NetIT is required so the Library's system can know who you are, but sponsored NetIDs need to be authorized by the library for content.
Thus, the PI's group must coordinate their group's library needs with the Library access folks.
Hopefully the Library is able to bulk-provide access if the PI provides them a list of all the sponsored netids related to the group.