This happens sometimes, but I don't think it's endemic. I've seen people come in a day late, even in questions where an answer has been accepted, and get tons of votes. It just has to be obviously much better than the others and you have to hope the stars don't align against you (as with so many things in life). The "fastest gun" problem typically occurs when the best answer does not really stand out to people.

For example, glancing at my top five answers, one of them was posted the day after the others in the question and got four times as many votes as the next top answer. I remember that at the time I wrote my answer, a very low-quality answer from somebody who didn't know Ruby very well was accepted, but now mine is accepted and the other guy graciously deleted his.

And that one's still getting votes. People come across those old questions and vote the good answers up years later. So the site can correct itself as long as people are willing to do that.