When do you suggest that they find time to 'study up'? Most corporate environments in which I have worked have an assignment:time ratio greater than 1:1. Often there wasn't an opportunity to take the legal statutory lunch break nevermind study.
Consider our industries project failure rate. I've been on projects where it was the new team on the new tech stack that's let go and the guys maintaining the 20 year old system get a huge boost to their negotiating power.