Engineers are valuable for what they can learn
This statement is also myopic and bordering on cliche. While true, there are a lot of times want to hire for a specific skill set. For instance, if there's a problem that needs solving right now, or a team that needs a new lead (assuming you must bring on outside leads), or a whole number of scenarios.
You should care about the delta of an engineer's career and knowledge
This is, often times, a great indication of how competent an engineer will be.