I hate the construct of work-life balance for the same reason I love engineering: the reality is dynamic and generative, not zero-sum. It’s about transcending the constraints of simplistic calculations. Creating the life and the work you want are by no means easy challenges, but they are absolutely attainable. What’s not realistic is thinking you can own your future and be comfortable at the same time. Grit, not virtuosity, will be the biggest determinant of your success, for reasons I’ll explore in a bit.
There is a raging debate on Twitter among the tech cognoscenti about this currently, and I've given a lot of thought to this subject, as I've gone through a sabbatical, an intense start-my-own-company period, and varying levels of work hours at a few large companies.
I whole-heartedly agree with work vs life being a false dichotomy. If "work" and "life" go in diametrically opposite directions for you, re-evaluate the choices you've made for one (or both).
Another term that always comes up when talking about work-life balance is "burn-out". Burn-out is real, but spending a lot of time working hard doesn't burn you out. Spending a lot of time doing something inherently unsatisfying or with people you don't like is what burns you out. And both of those can usually be traced back to work or life choices you've made (and are often fix-able, once recognized).
Also, grit and resilience are the most under-appreciated qualities of our age. It is a wonderful article. Do read it.
All this doesn't mean I'm advocating for working all the time, all your life. Work patterns are changing in the new economy, that require effort at a different cadence, as aptly put by @naval:
Forty hour workweeks are a relic of the Industrial Age. Knowledge workers function like athletes - train and sprint, then rest and reassess.