Great point: This is true of every high level metric. (Delivery, profit, ‘quality) or medium level metric (OEE, Warranty, Complaint Rate…) Even many specific single characteristic dimensions often cannot tell you what is causing the problem only that something is a problem . We still need to investigate. Hands-on, boots on the ground observation and diagnostic experimentation (aka Problem Solving) Some of the current ‘revulsion’ and minimalism about metrics
Unfortunately too many people think only of perfection in the metric or think that every metric must meet the target every time or every metric not meeting the target must be worked on everyday. ‘Aspirational’ targets are set in hopes that even if the target won’t be met, the ‘efforts’ will at least better than if a ‘realistic’ goal is set: Banners and exhortation! Deming was on point when he said that ‘goals’ without a method of monitoring them, understanding them and improving them were foolish.
Fortunately the OP seems to understand at least part of this: focusing on ‘on time shipment’ and why there are misses to identify the causes and improve performance. They understand that the misses are driving customers away and this will not support growth (especially in the automotive industry). Unfortunately their management is stuck on ‘do better, try harder’…