Googling gives someone time not just an answer. Sure, for trivia an answer is all you need, but trivia is a waste of interview time. On the other hand if someone looks up a formula they can spend 5 minutes actually understanding it which feels like an eternity in an interview.

Remember the context is the Job not the interview. On the job, having not done something for 3 years is a minimal setback for most people as the retraining time is almost meaningless. In an interview that 'highly' skilled person is going to take a long time to get back up to speed.