Attacking a large organization through social engineering is only possible when you pair it with widespread, badly designed automated systems. That doesn't just mean electronic systems, it also means things like forms, and rigid process, and anything else organizations do to increase productivity at the cost of decreasing thinking.
You might be able to social engineer one retail worker into opening their cash drawer, but it's impossible to clean out them all because the attack doesn't scale. ACH lets you social engineer one banker into bankrupting an entire company. Things like SCADA in utilities, business intelligence databases, customer relationship management systems, government taxpayer records,... they don't just increase the electronic attack surface, by their basic productivity-enhancing function they massively increase the social attack surface too.
This attack surface grows exponentially with respect to the utility of automation. There's no way to win this game, least of all by throwing money at it.