Most people have other interests or hobbies that don't align with their current job.
Even if you enjoy your job, leisure time is still important. Besides, even if your job was the reason for your existence, if you're constantly stressed out, you'll burn out and not enjoy it any longer. So, even if you have no interests outside of work, you still need to find ways to lower stress and decompress.
For high-skill labor, the problem here is can be attributed to corporate culture.
Take Japan as a extreme example. They work some of the longest hours as proven by the chart and other sources. But, there is a culture where leaving work early is generally frowned upon even if your work for that day is done and staying at work late to creates the perception of being a hard-worker even if you are productively able to accomplish very little. This culture exists in other first-world nations as well.
I suppose part of the problem here is that many places management expects workers to "look busy".
THis leaves little time to actually contemplate a problem to find a solution. Often times I find that staring out of the window, going for a walk, or playing a mindless game for a little while. Allows my brain to process things in the background. If I have to "look busy" I might just be banging my head against the same mental wall without progress. But hey at least I "look busy" so obviously that means I am a hard worker.
Something else to consider, though, is that work-life balance isn't simply dependent on how much time you spend working.
One of the most common strategies that companies use to improve work-life balance are flex-time and flex-place policies.
A country with large populations of poor people are going to be working longer hours, or even multiple jobs, just to make survival wages. On the flip-side, you have a lot of the Nordic European countries, like Sweden, Denmark, Finland, Norway, that are among best countries for social welfare programs that even allow the poorest to have a decent life and free education.
As the OECD explains it "Percentage of people who are wroking 50 hours or more a week on average for the past year". You can find more info and more details per country on the OECD page.
