No. By the time I'm relying on the white line to see my lane, I'm already driving at half-speed.
And the lines are absolutely invaluable to people with certain visual issues, like poor ability to see color contrast (like along the edge of the road) or less than stellar night vision. Having the line means people with imperfect depth perception or imperfect space relations don't have to GUESS where they should be on the road. It prevents them from becoming a hazard to others when they can't decide where their space begins and ends.
(Cue the elitists who'll say such people shouldn't drive in the first place.)
Someone mentions driving on snowy roads where you can't see the lines anyway as evidence that they're not needed. This sorta neglects to notice that on such roads, unless there's an obvious obstacle, people tend to drive right down the middle, as if it's a one-lane road. I've seen this produce collisions (even at very low speeds) at blind corners.
Another issue that comes to mind is legal liability. If a vehicle takes its half outta the middle, hey, there's no lines saying they can't. So now who's at fault when you have a head-on or drive off the road because two drivers disagree (and YOU might be the wrong one here) on what constitutes their fair "half" of the road? "I thought that WAS half the road" will become the go-to legal escape.