Due to selection effects, I wouldn't find it too surprising that the "middle of the road" (ie. 50th percentile) of developers with a job is equal to the 80th percentile of developers seeking a job.
Well, the reason I was able to apply both "middle of the road" and "80th percentile" labels to the same code is because the former was regarding code quality and the latter was regarding code prevalence (in the same sense that scoring 50/100 on an exam doesn't necessarily put you in the 50th percentile).
As far as developer quality goes...I'm afraid I'm not qualified to comment.