I don't think people lied about their expertise. Instead, they likely believed that what they knew was sufficient for their work. Another possibility is that th

I don't think people lied about their expertise. Instead, they likely believed that what they knew was sufficient for their work. Another possibility is that the big tech hired so many people in the past few years that many people ended up doing bike-shedding work. They could be excellent engineers in the past, but as time went by, their skills got rusty yet they were too busy to be aware of it.