AI is eliminating entry-level developer work, but there's a less-discussed second effect: senior engineers are quietly losing their skills by only approving AI-generated output rather than doing the work themselves. The 'reasoning muscle' atrophies when judgment is never exercised. Meanwhile, no new seniors are being produced because the junior work that used to forge them is gone. Practical countermeasures include deliberately doing one thing the hard way each week, asking AI to defend its choices rather than just accepting answers, keeping a log of AI errors, and giving juniors the 'boring' work instead of offloading it to machines. No systemic fix is coming — individual engineers must maintain their own skills deliberately.