I can't say mismanagement at all. What I can say is misalignment of incentives. You ask people who will not be in charge of paying what they want. Of course, they will want the best for themselves and for the generations to follow, but the people who have to make the decisions are not experts in that specific area, and they don't have as clear an idea as to the costs of this or the alternatives.
The incentive alignments are not perfect, to say the least.