Recently, I read an article where someone commented that work life balance is a privilege, and not an entitlement. It's only for people who has worked so hard to show their importance to the company that the boss has no choice but to accede to their requests.

I disagree somewhat. Work life balance is a choice. Our commitment to the company is 9am-6pm on weekdays. Other time should be ours. Of course, when work is not done, we should be responsible enough to use our own time to complete it on time. But then, I would say that free overtime by employee should be a privilege, not entitlement of the company. The company should try their best to let the employee go back on time everyday. Of course, the employee should also be trying their best, do overtime if necessary, to complete their work on time. After the employee had put in a reasonable amount of time into his work, then he should be free to spend the rest of the time on other important stuff.