Work life balance is the employee self discipline.
Company cannot make you leave or make you stay after work.

6pm bravely walk out the door.
If you're willing to work for free for company at your personal time.
Go ahead.

When you're sick... You go to clinic to see doctor. Doctor close at 9pm.
You go bang the doctor door at 905 pm.

Doctor don't open the door.
That's work life. Balance.

Come back tomorrow he said.
Or go to the hospital A&E.

Work life balance is like going to a gym and have 6 pack.
Everyone can be muscly and 6 pack abs.

But only a handful people in this world have.
Why?
They have the discipline to work their body.

Likewise if you lack the balls and guts to champion work life balance for yourself.
Go ahead.

I won't be wishing "if only I stayed back at work just 1 more hour" when I'm dying in the hospital bed.