Traditional thinking says if you earn more per hour than you're paying for stuff like that then it's a net win, but again that is a business idea (opportunity cost) and doesn't work for individuals. If it were true, everyone earning more than minimum wage should be paying someone to do every single thing in their entire life... but that doesn't work because you can't just earn more money when you're on salary, and you don't have infinite hours to work endlessly more.

This analysis totally ignores a whole bunch of factors, including that you can’t pay someone else minimum wage for a bunch of things, and that “hiring someone to do X” has a huge transaction cost associated with it. Not just the hiring part, but the coordination, etc.

The “can’t work more hours” piece actually works towards your argument for finite time: why would you want to spend any of your outside-of-salary time doing stuff you don’t want to do that could pay someone less to do?

Time is not fungible.