It doesn't even take oodles of money from a SaaS platform to motivate turning a library into a service.
Even in in-house development, developers are often motivated to build services and have internal customers take dependencies on them so that they can expand influence and demonstrate ownership in a way that gets noticed by senior leadership and put them in line for promo. It also opens up the possibility for stakeholders to build their own little fiefdoms with access controls, intake processes, and a justifiable source of funding.
Even in in-house development, developers are often motivated to build services and have internal customers take dependencies on them so that they can expand influence and demonstrate ownership in a way that gets noticed by senior leadership and put them in line for promo. It also opens up the possibility for stakeholders to build their own little fiefdoms with access controls, intake processes, and a justifiable source of funding.
Can't do that with a library.