Actually, people are supposed to use both lanes up to the merge point, then "zipper" together. Traffic moves a lot better when that happens.
Now, does that ever happen? No. Humans use their common sense, they move over when the signs say a lane is closed ahead. Then we get mad at the people who "cut in line" by zipping up the open lane and cramming in ahead of us.
I move over early too, and I get mad at those guys as well. I do know people are supposed to use both lanes, until they can't. It just doesn't seem polite.
Okay, full disclosure. I lived and drove in NYC for almost 10 years of my life. In NYC, zipper merging is a fact of life. All lanes are slow as they are all completely full.
I now live in St. Paul. Driving in MSP is a breeze now, except no one knows how to merge correctly. I love the fact that lane closures get people all lined up for a mile or so ahead of the actual merge. Yes, I'm one of those guys that flies by everyone in the open lane and merges in at the last second (typically without any issues as the gaps in the midwest are already typically big). Use to feel bad about it, but when getting my MN license I saw the zipper merge link on the FRONT PAGE of the MDOT website... As far as I'm concerned, people can continue to be polite, but I'm going to do it right. Knocks 5-10 min out of my commute every day. Also, unless the idiot I merge in front of slams on their brakes without reason, I assure you that I don't slow down the column of traffic. As mentioned previously, people leave big gaps here, so it's easy to get in and out. The slow down is typically due to semis and slow acceleration when they get going.
The best part is the people that see you coming and pull into the lane half way to try and prevent you from passing. (I actually used to do this when I didn't know better.) Usually they aren't aggressive enough to block the whole lane so I typically drive right around them and honk.
There's polite, and there's not being educated... Until everyone catches on, I plan on taking full advantage.
Also, the left lane cruisers in Iowa are incredibly bad... It really is an epidemic. At least they merge right away, though they usually come to a full stop when they do.