Why IT Transformation Programs Keep Paying for Systems They Declared Eliminated

A concept called 'dependency residue' describes the hidden costs that persist after a transformation program officially decommissions a system or platform. The problem arises because cost models track expenses along accounting boundaries — invoices, contracts, subscriptions — while actual dependencies run across identity, data, network, and operational layers that rarely align with budget lines. When a program declares something eliminated, it validates the claim against the cost model's boundary, not the dependency's, leaving service accounts, backup jobs, audit rights, and vendor obligations silently active. The pattern was first identified by Rack2Cloud within cloud repatriation scenarios, where compute workloads moved on schedule but identity and CI/CD layers remained anchored to the exited provider, keeping costs alive. The framework has since been generalized to apply to any transformation program that measures closure against a line item rather than the full dependency footprint.