It's becoming clear that libraries can pick and choose from a variety of digital library products independent from their main ILS platform. These products include open url resolvers, federated search systems, e journal management services, digital asset management systems, and most recently, next generation catalogs.
It's now possible, and perhaps even common, for a library (or a consortium of libraries), to have an aging, but reliable ILS performing the basic inventory management functions of the 'bought' collection while a bevy of other digital library products peform the new digital library functions mentioned above.
But what about the vendor of that core ILS product? Is it not likely that prior to these disconnected array of digital library products, they were able to reliably sell upgrades and add-ons to their installed base of ILS customers? Now, they must face competition with many other vendors for finite resources that libraries have for new technology. It might also be likely that this vendor isn't positioned that well to compete against some of these newer, more nimble firms out there in the digital library marketplace, and that even thought they offer digital library products, they have trouble selling their products even to their existing base of customers.
What is this vendor likely to do in this situation? Simply sit there, idly supporting their aging traditional ILS system and watch their chunk of revenue from the library technology marketplace decline? That would be pretty painful, I imagine.
The easy answer, of course, is that they need to reinvent themselves, innovate, and regain market share. But if that doesn't work, there is another option. Even though the traditional ILS is losing some of its strategic importance for libraries, it is still a core part of a library's operations. And generally speaking, libraries depend on their vendor's support to keep these systems running. Specifically, they depend on a support contract, which is a voluntary agreement between two the vendor and the library. If a library system vendor doesn't like how a library (or perhaps group of libraries) is spending its money, they could simply threaten to discontinue that contract in order to bring the library into line. After all, most libraries would be hard pressed to switch ILSs on short notice as it is quite a costly and time-intensive undertaking.
Of course, this would be a dangerous game to play for a vendor in the long term, as a core ILS can be replaced with plenty of different options. But it is one tactic that a desperate ILS vendor could use against libraries in the short term.