Same here, I imagine other industries are this way, but software (or maybe let's say clumsy giant enterprise software) benefits a lot from one person working 60

Same here, I imagine other industries are this way, but software (or maybe let's say clumsy giant enterprise software) benefits a lot from one person working 60 hours rather than 2 working 30 since so much of the effort is actually keeping the cruft and procedures in your head, which is a fixed cost. Clients want to meet with your development lead, who you also need to be doing actually development; and if meetings take up 20 hours a week, 60 hours is actually 4 times as many working hours as 30 not just double. Not to say it isn't a little bit of a sad state of affairs.