It's true that custom prompt engineering and integrated workflows feel like a sunk cost, but if a better AI provider appears, we need to ask: would we re-enter that same contract today, knowing what we know?
My experience auditing IT budgets shows that management often chases a losing idea because of the initial investment, even when a cheaper, more efficient alternative like an API-based model could be implemented with minimal switching costs.
If an alternative offers 20% savings and the change is just re-pointing an API, the "friction" argument doesn't hold much weight; you dispose of the old system.
We've seen it with old server contracts; once a cloud solution emerged, the previous "investment" quickly became a liability rather than a lock-in.