The structural problem
A separate CCMS infrastructure is a parallel IT estate to maintain
When the CCMS is a separate platform, IT has to operate two of everything: two access-control regimes, two audit-log destinations, two data-residency stories, two disaster-recovery plans, two license agreements with two procurement contracts. The CCMS team manages the platform, the IT team manages everything else, and coordination across that boundary is what consumes the project.
The cost is not in the license fee. It is in the procurement, the security review, the data-residency clearance, the audit-log integration, and the parallel access model that has to be reconciled with the corporate one. For a regulated-industries customer every one of those reviews is a multi-month exercise, so the evaluation takes longer than the implementation and the conversation becomes about platform fit rather than content design.