Not because the campaigns are ignored. Because the system feeding them is incomplete.
Google Ads is a machine learning system. It optimizes toward whatever data you give it. If your conversion setup is tracking the wrong thing, your CRM isn't connected, and your landing pages are vague — Google gets very efficient at generating cheap, unqualified leads. The campaigns look fine. The business outcomes don't.
Most agencies stop at the campaign layer. The conversion setup, CRM connection, landing page quality, and message architecture either don't get touched, or get fixed once and forgotten. That's where the performance gap lives — not in the keywords.