Getting employees to work hard and deliver really isn't a matter of mandating work-from-office and long hours. It's a matter of incentives and ownership. People do their best when they work on interesting problems, in a self-directed manner, and get rewarded for success.
This is true regardless of location and schedules.
Inversely, if you don't get this right, it really doesn't matter how long your employees stay in the office. I've seen the office culture in Japan.