This is simply wrong. Quality starts in the basement, and works its way up. So if you monitor a system at the lowest level you will be able to build confidence about those layers and you will spot trends
long before they will become apparent at higher levels
because those higher levels will erase the fact that at lower levels things are already going wrong.
Systems that only monitor the highest levels appear to function fantastically well right up to the moment they crash spectacularly. Then the forensics will show you that at lower levels there were plenty of warning signs telling you that the system was headed for the cliffs and a large number of those signs will be apparent while there was still time to do something about them. Reliable systems engineering is not something you can do just at the highest levels because of the build in resilience in intermediary levels. This is counter-intuitive but born out in countless examples of systems that look robust but aren't versus those systems that really are robust.