Not sure how much you've been watching the campaign, but it's pretty clear that a huge chunk of those people only voted "no" because of the panic concession promises that the party leaders in Westminster made a week before the vote, when it looked like the "Yes" campaign was making ground.
I don't think it's fair to decide why anyone voted as they did. I couldn't find anwers to many basic questions so couldn't that equally be the reason? Can we declare that "yes" voters did it for some reason that we want to attribute to them? People voted how they did because they believed it offered the best future for them and their family - if that was "no" then it's because the "yes" camp didn't convince them that their vision of the future was a better one.
I actually think the late promises and concessions were a mistake and unecessary. These types of referendum nearly always have flattering polls with people backing away from the choice when it comes down to the final vote.