One reason is prioritization. It’s enough to know what the effects of the failure were, the likely cost of what needs to change, and what areas and processes the changes will affect, to decide if and when this should happen.

Leadership still needs to understand these aspects on a conceptual, topical, and cost level to decide on the resource allocation (including time and schedule). They don’t need to understand the technical details, unless they are a technical leader with higher relevant technical competence than their reports.