If the goal is to be happy and if some people find greater happiness doing 'work' while others find greater happiness devoting time to 'life', then surely there will be some people who will split their time accordingly.
Maybe it's not technically 'balance', but do you really think when someone says 'work-life balance' that they mean 50-50 split between work and life? When I hear it used it usually means 'spend less time on work and more on life', and I think hippo33's is correct: not everyone needs to (or should) spend less time doing work because that's where they may find the most happiness.
We both (along with hippo33) agree that everyone does not need to lead a balanced life. There are other valid choices like a life of dedication to a specific cause or pursuit. Or anywhere in between that makes you happy.
We disagree on whether you should use the word balance when you "technically" mean the exact opposite. That's poor communication in my opinion.
Maybe it's not technically 'balance', but do you really think when someone says 'work-life balance' that they mean 50-50 split between work and life? When I hear it used it usually means 'spend less time on work and more on life', and I think hippo33's is correct: not everyone needs to (or should) spend less time doing work because that's where they may find the most happiness.