It's been proven repeatedly during the last 100 years that overtime doesn't work. Yet it falls on deaf ears in my industry. I've worked for 10 years in games development. Every single company had unpaid mandatory overtime. It's depressing.
Here's a solution. Pay your employees for overtime - suddenly you'll find a way to not do it. But it's too late, because it's now accepted (and expected). Even though it's counter productive.