Googler here. I used to feel very guilty during my first year here, because my productivity was so ridiculously low. Yet I was being praised for being fast and productive (both by my team, and by my manager).
Then over time this feeling started fading away (since I could clearly see that everyone was unproductive, not just me), and I started seeing this as the new normal.
Everyone works way below their potential, and a lot of time is wasted through internal processes, subpar development tools, and massive overengineering.
Part of me believes that many people are hired so that they don't go build competing products.