this is already done; this is what modelling and simulation is for. at least in the US pretty much all projects require some kind of alternatives analysis, and

this is already done; this is what modelling and simulation is for. at least in the US pretty much all projects require some kind of alternatives analysis, and at least one of those alternatives must be "do nothing at all." whether the model's assumptions are correct, and whether politicians actually allocate funds based on projected efficacy, are another matter entirely.