We became a "connected" society that has to be in touch 24/7. Companies we work for, and our customers expect 24/7 productivity. Our bosses expect to be able to reach us morning noon and night.
Personally, at the end of the work day my cells phones all get turned off, and my boss knows I won't answer a business call. But it's a struggle and in the end likely to result in me not having a job because for everyone like me who won't slave away for 60, 80, even 120 hours a week there are 100 more who will do it happily.