I appreciate the idealistic take on what a "principal" role should be like, but in all actuality, principal engineers are commonly the ones that simply stayed there long enough (ie. to survive multiple re-orgs), and played their politics cards wisely. They were playing the title game. Often, their work is invisible to most. They perpetuate tribal knowledge, and have trouble letting go of the past and accepting change.

You'll notice plenty of comments here from people who claim to be principal engineers - stating that they "kinda follow it all". I wish we could talk to their colleagues though (the juniors, seniors, PMs, tech-leads, support/escalation engineers, as-well as other principals).