What is Missing Idea: show how long it's been since an ingredient was available

[jweather]

In my mind there's a difference between "What's the bottleneck" and "why isn't this working", and it would be cool to easily be able to see "electric engine units haven't been made in 5 minutes" as opposed to "you need more electric engine units to make this faster, but one was just available 5 seconds ago so it's not actually broken". I don't know if that would be a timer on each icon, or just highlighting them in shades of red as they sit idle for longer. Thanks!