Like for deadlines : most of the time it isn't. People can get new jobs. You can found a new company.
But burnout is like losing a limb : you will never be able to operate at the same level again (not to mention the months it's going to take before you can start do even part-time work again).
There are very few situations where such a sacrifice would be worth it. Probably only those involving family members, and consider that after that they will have to deal with your now relatively crippled status for the rest of your life.