Let me make that clear: she does not talk about healing burnout or that it isn't grave. Marissa just talks about how to avoid to get it in the first place.
Please read her full post at Bloomberg Businessweek which she ends with:
"So find your rhythm, understand what makes you resentful, and protect it. You can’t have everything you want, but you can have the things that really matter to you. And thinking that way empowers you to work really hard for a really long period of time."
I follow her on that, knowing so many people working really hard, but finding their inner and outer balance by not neglecting what makes them really tick in life!
And, yes, the employer has a great responsibility in supporting that with the right means.