Could the U.S. adopt an eight-hour workday? In my experience no.
But I'd rather formalize the 10 hr workday and switch to 4x10s. I think it's superior to 5x8s because you can get longer continuous periods of work and an extra day to actually rest/recover.
I don't really see 6 hr days working in office jobs. With emails, meetings and lunch, I feel like I don't really get going until 3pm.
I think what needs to happen is an increased in flexibility. To me it seems that society has done a piss poor job in figuring out how to accommodate to women and new types of knowledge work - which requires a lot of flexibility.
That sounds like a really wasteful work environment. You spend tremendeous amount of time just synchronizing with people. That's just bad management and lack of vision from your employers part, not a law of nature.