You're missing one more on the company side beyond TCO: there's definitely an element of multiplicative productivity from not only avoiding duplication of effor

You're missing one more on the company side beyond TCO: there's definitely an element of multiplicative productivity from not only avoiding duplication of effort, but getting the stuff everybody does done incredibly well via a collaborative effort amongst those who all share the same problems, such that they can focus on higher value added work. E.g. database, OS, machine learning libraries... A real life example might be a small town in an emerging country [1] where retailers band together and invest in building a road to the big city nearby. This greatly increases their revenue by bringing in a lot of traffic that wouldn't otherwise have bothered, even if the ROI on the road, if measured purely in terms of money in money directly out, is "negative". [1] I read about this happening in regions of Iraq. I saw it in person in the state of Maharashtra in India, where Godrej is building roads and power plants in the region around its factories near Pune.