A shortage of skills is often the interpretation people get (or at least voice publicly) when they think labor costs are too high.

e: Not that I'm arguing that it's the case (or the alternate). You'll run into business politics, politics politics, lies, lies people tell themselves, and statistics before getting any actual insight on the issue.

The only convincing argument I've heard is that wages aren't increasing to match the reported demand. Which doesn't indicate anything directly. It suggests sufficient labor pools but rests on the assumption that if there are insufficient talent pools employers would pay more to attract talent.