It's not healthy for the organization as a whole if the only point of contact between "the business" and the developers is enshrined in the Product Owner. It is however very amenable to empire building and short-term cost savings, both of which are examples of a manager favouring their own interests over that of the organization. In short, Scrum is most useful for those for whom a dysfunctional organization is their goal. That the turkeys (devs) are voting for Christmas themselves is the icing on the cake.
It seems to me that this question depends very much on the kinds of commitments management is making. Which in turn depends on whom they are making them to. If it's to a customer that has some hard requirements, enumerated in a contract, and providing those is the source of money, then management's focus is (and should be) executing those requirements. Which would seem to imply that a black box is just fine.
The problem is not the desire for a black box approach, but that boxes fail. Management is risk averse (and their risk aversion is what keeps your paycheck coming, in theory).
(Actually, black boxes are creeping into software development all of the time. For example, there's no reason to not have fast PSD-to-HTML turn-around anymore. That process has been black-boxed. Not shrink-wrapped, but black-boxed. Yes, there are still quality variations, questionable use of excessive markup, etc, but its not bad.)
Anyway, I just question your tacit assumption that management wanting a black box with a well defined interface is a bad thing. It seems like a reasonable goal.