Beware Dumb Hot Rod Shops

your line in there about the staff turnover makes me think that it's "an institutional problem" with the mechanics probably being decent but somebody up the chain telling them to just do as they're told and ship it.
I agree, but with a caveat.

As bad as this may be I don't see it as "institutional", or even "industry wide", but rather "generational", if I may use that term. The Boomers are retiring, and more often than not taking their knowledge and experience with them. Not because they want to, but because there isn't anyone following in their footsteps.

As an example, at our shop (Mechanical Contractor) we simply can't find the bodies to do the work. The older guys are retiring one by one, but there's no one available (or interested?) in taking their place and gaining their knowledge. We have two Unions in our shop (Sheetmetal and Pipefitters), and while even for Pre-Apprentices the pay is pretty damn good, we still can't seem to find guys interested in joining the Trades, Union or not.

And with the Knowledge Base retiring....

But the Owners and Managers still want their EOY Numbers, so the work gets "pushed", and sometimes it's shoddy and/or things are missed.

Sadly, "Numbers before Quality" seems to be the Rule of the Day these days, in my opinion. (Hmmmm! So maybe it is institutional after all!)

Anyway, just my $0.02.