I don't think it really is the 4th line. IMO, that's the 2nd best line on the team, and I think that will reflect in their icetime.
One thing I'm wondering about is Kovalev as captain. Don't get me wrong, he's a good player and a good guy and all, but I just don't see him as the type to captain a team, especially an Olympic team. Although looking on the roster, I don't think I really see a much better option. I think Ovechkin may get the C 4 years from now, but I'm kind of surprised that Russia doesn't have a better alternative at this point. But that could just be the "Euros don't make good captains" mentality sneaking out.