You seem to be referencing as core business value a combination of (1) the ability to maintain a (2) business criitical resource, but stating it as if catastrophizing from a hasty generalization. Can you clarify?

It's really not that simple. A lot of what's involved is fungible. Of course, the answer to "Was the greatest intelligence harnessed to make the greatest decision?" Is always no.

AIs can be swapped for one another, run locally, and implemented in ways that are less prone to loss of function. Loss of anyone who understands the working code is a type of risk, but that kind of issue tends to bounce between losing skill from lack of foresight due to economic savings, and overhiring / bringing back lost employees as consultants.