One of the most power tools that economics have brought to the world is cost-benefit analysis and really assessing what is the constitution of cost or benefits at various levels: individuals, firms, regional government, national government, countries.
Where it fails is the ability to properly ascribe who cares about what. The assumption around rational, selfish agents cannot possibly hold in reality. On the other hand, there is radical inconsistencies when you perform such optimisation on behalf of “government” which is staffed by human agents and with politicians have their own agenda. Over the years, these poor assumptions have made room for more colourful, richer analysis of agents, decision-making units at different levels.
Now if we move our attention to the dimension of time rather than perspective of our agents, we realise another issue. We can assess somehow the cost and benefits of today if we use our imaginations but to stretch it to the future would require even more manipulations. And the uncertainty make render the exercise less fruitful than one may expect.
Alas, we continue to use these tools expecting them to work while not having proper assessment of whether they work or not when the outcomes play out in reality. It is not the issue of calculating those figures but how we incorporate them into our judgment that matters. Yet with limited budgets and resources, most have chosen to opt for a semblance of the exercise, paying a smaller cost but getting almost none of the benefits.