Everyone who doesn't have a personal stake in the game is naturally inclined to act recklessly. See the decade-ly cycles of recession and depression economies slip into when markets (housing, finance, oil, whatever) forget that someone else's money is still of value and not to be treated with total abandon.
The decisionmakers at ISPs don't have a piece of skin in this fight because they have special classes of access just as a benefit of being where they are within their companies, and they stand to make more personally from making profit-minded decisions. For these reasons, there's very little personal incentive to uphold the moral high ground because the decisions don't have an immediate negative impact on them. They might feel it once they retire and/or if they go to a different industry, but that's after they've made their profit, and it's long after their short-term decisionmaking window.
It's just human nature. We haven't had this trait bred out, and it's doubtful we as a species ever will. The only way to counter short-sighted thinking is by shortening the mental leap between short-sighted decisions and long-term consequences, which is what everyone fighting for net neutrality is trying to demonstrate right now by citing live examples of where a lack of enforcement has already gone wrong (T-Mobile Unlimited Music, Netflix v. Comcast/VZ, etc.)