Very experienced software developers can be incredibly deluded about the quality of vibe coded output esp. for large scale feature work - see the SBCL discussion on fibers https://sourceforge.net/p/sbcl/mailman/sbcl-devel/thread/CACxje5-Nwfoe8REix2B8KGksLi31OSW0A32LQbfCccrpM1R1%3DA%40mail.gmail.com/#msg59302483 - worth reading closely. A proposal/implementation that took a couple days to vibe now has no specific timeline to address all the issues raised by reviewers.