If everyone does, great — traffic moves smoothly.
If a bunch of you refuse, great — we will merrily zoom past you in the empty lane.
I have almost never been unable to immediately merge at the actual merge point. Yes, there are some cretins who try to block that, but I have personally witnessed cops ticketing for it (and it was glorious).
Maybe some of you are more surrounded by troglodytes who fight the merge, but I don't believe that that kind of ignorant, bigoted behavior is at all prevalent.
Feel free to be crabs at the bottom of the bucket all you want, but you will never stop the rest of us from reaching the sun. Perhaps one day you will join us there and feel its beautiful warmth.