Friends that have never worked virtually ask "isn't it hard to stay focused on your work?" Quite the opposite. It's hard to stop, to not listen for a 'ping' of a new email that needs you at night, not signing in on weekends.
But maybe that's OK. As this article states: it's about achieving the mix of business and personal life that's right for you. For some, answering that email when it comes in at night might mean their next day is smooth.
We all have a responsibility to complete our tasks, achieve the goals, actively participate, and yes, put in the time. I think the real answer is to make sure that you love the work you do. That makes the balancing act all that much easier.
Life balance is a subjective concept. You may love spending most of your time at work, and that's fine; there's no need to feel guilty about being dedicated to your job. As long as you feel happy and balanced, there's no need to change!