I worry less about chain of trust and more about continuity of business: it's not enough to be a able to stay running, you need to be able to keep delivering features which means your build infrastructure and data needs to be local.

I.e. if someone cuts all the undersea fiber optics, what do we do? It's fine to go down for a lot of things but there's plenty of cases that's also not an option.

This is absolutely one of my reasons. When the internet goes down I have every line of code that built my system from zero right here.