I'm using the royal We here, but it's an honest question. Blog posts announcing one's decision to quit are apparently shocking to some people, but for the life of me I don't understand why. When lawyers quit does everyone stand staring, mouths agape? What about when doctors chose to do something that isn't clinical?
A PhD is a highly variably degree that trains you for a lot of things. One of those things is a job in an academic setting, but there are others. This post isn't about job shortages or "alt careers" (which is a misnomer in itself), but a PhD is more flexible than it is often cast.
Being a PI is a hard job with it's pluses and minuses, just like any other competitive career with a lot of training. There are pressures and stress and constant rejection. At times things get overwhelming and you're pulled in far too many directions. For every person who appears to lead a charmed life, there are ten more who spend 40% of their time battling bureaucratic red tape. So why is it shocking when people find another opportunity that they want to explore?