I assume they are mostly unrelated skills, my mental assumptions work something like:

Suppose the top 10% of developers break down: 1/3 are noticeably worse than average and take 6 months to find a job, 1/3 are average and take 3 months to find a job, and 1/3 are above average and take 1 month to find a job. Each month 3000 people or 100 good 100 average and 100 bad start looking for work and the number of people looking for a dev job is 10,000.

Our of that 10,000: 100 are great developers skilled at finding jobs so 1%. 300 are great developers that are average at finding jobs so 3%. And 600 are great developers that are bad at finding jobs so 6%. That’s still 10% of applicants but most of them don’t look as hot in interviews.

Interesting! I've never before considered the dimension of time, which will lead to accumulation of brilliant interview flunkers.

The only assumption that remains to be tested then is that our current practices do not identify developers that belong to, say, top 10%.