This is all very true for a small startup and some kinds of skunk works projects.. Many companies Google's size don't allow you to work that way in general, and in some sense don't benefit from it because gaps caused by no need to write things down are too hard to fix later and more critical to them than not shipping at all.

If I had to guess, Google's problem is probably that they created ephemeral written text as the primary solution for communication. It is neither good for speed nor good for documentation as a consequence.