&gt; The fact that those things don&#x27;t have a return of 15% shouldn&#x27;t be a justification for, we, as a society, not doing them.<p>Isn&#x27;t it, though? Doesn&#x27;t ROI define what it means for something to be &quot;worth doing&quot;? If you think we should be doing X and X is not currently profitable, what&#x27;s effective isn&#x27;t expressing disappointment that X isn&#x27;t being done. What&#x27;s effective is changing the incentive structure so that X is profitable.<p>By the way, it&#x27;s not a 15% return that&#x27;s necessary. Right now, the current reserve on US federal bonds is 2.56% over 30 years. Investors are buying these things like crazy. It&#x27;s really fucking sad that our society is so hard-pressed for things to do that 2.56% over 30 years looks like a great opportunity.