On the other hand we have had a bunch of demo prototyping APIs built that ultimately weren't adopted as the client needs changed, and because they were built wi

On the other hand we have had a bunch of demo prototyping APIs built that ultimately weren't adopted as the client needs changed, and because they were built with Lambdas, it essentially cost nothing to run them. While having servers run for a couple of years before they admitted that priorities had changed and they weren't going to use it but could we built them something else would have had a cost attached to it. Cloud was cheap in this scenario. Planning, determining your usecase, workload, and you can usually get a good idea for cost comparison. Especially if you have PBs of data storage costs, data centres or even having local hosting can slash costs. People are usually pretty bad with risk/cost management.