John Carmack is highly successful in software and has a poor work-life balance. Doesn't mean there's causation between the two.

If there's an emergency, sure, work 12 hour days until it's fixed. Maybe if you're really in the zone, go ahead and keep working for 12 hours once in a while.

But, being behind schedule is not an emergency. And if the emergency continues for more than a couple days, it's a situation, not an emergency. 12 hours of focused work is hard to do. And if it's not focused, might as well punch out at 5, live your life outside of work, get some rest, maybe let problems marinate, and come back tomorrow.