Unfortunately, until we see a company be successful while breaking the rules (not eight hour days, no open workspaces, etc), the world will continue the same. Maybe when we HNers start a company or startup we should actually do what we post about constantly.
I believe that eight hours is too much. Working eight hours a day (plus commute, however short it may be) leaves you little time for leisure when you add the chores of daily life. I rarely care about how the company is affected, so I am glad studies like these exist.