One thing to always keep into account is this is no contract. You can get into institutional management/research, put 60h weeks, then leave for some place else with less hours but where your experience will be highly valued.
Long hours does not only equate large pay, it also equates valuable experience. If you wanna do more with less, more hours is often the solution. Also keep in mind that you're not working 60h+ weaving clothes like a slave at 10cents/h. You're doing high finance. Restaurants, going out with sales (they'll be the ones paying), reading and researching on a lot of interesting subjects, travelling (sometimes), etc. If you're good at what you do, tell me how exactly can 60h/w be all heavy workload.
Family probably is the only opportunity cost to that. That's why it's a good thing to put a *lot* of hours when you're young, trying to learn as much as possible, making contacts, and building experience twice as fast as someone with 40h work weeks would. That way, within a few years, you may even get to go your own way, at your own speed.