The might be applicable to some, but if he works in finance, there's a possibility that the compensation is heavily performance-based, and high enough that it is much smarter to focus on maximizing that (while investing/saving it) than it is to spend non-existent free time on side projects that might pan out to something eventually.

At a certain level of income from a job, it can very much make sense to pour everything you have into it to maximize your personal return while you can.