> Eg. I've seen people convince a public company executives to do strategy X based on analysis Y. Then when things aren't going as promised I get asked to review the strategy, I might find some elaborate model where somewhere deep in the layers of math/logic/lookups, someone divided instead of multiplied or something like that.

Is it Excel-specific though? I've made these kinds of errors with Excel (though not with stakes this high). I've also made them a lot when doing math on paper. And I've also made them in C++, Common Lisp, Matlab, Python, R and JavaScript. Now, with those other tools, it's easier to spot an error in a formula on review - but in Excel, it's easier to spot the intermediary results being off, so it's a wash.

I think the thing to learn is to be more careful, to sanity-check intermediary calculations; these kinds of errors are about being momentarily confused, and will happen regardless of the tool you use.