Almost anything you focus yourself on would benefit greatly if you were more fit and taking care of yourself and making yourself grow (both mentally and physically) doesn't take that much time. I currently spend 1 hour per day for 5 days at the gym. On top of that food prep and other training related stuff, lets say it takes me 2 hours a day. Everyone can find 10 hours per week if they just time track what they are doing. For me it has pretty much mean unsubscribing from Netflix and way reduced Youtube consumption.

But true your milage may vary, but usually it is just discipline issue. People want instant gratification and do not want to wake up early to hit the gym before they head out to work.