The ultimate “vendor independence” is racking your own servers in your own on-prem data centre with multiple internet connections. Very high capex, potentially low opex depending on scale. In the middle would be racking your own servers at multiple DCs. Less capex (you’re still buying servers, but not air handlers and power distribution), higher monthly opex. On the other end are things like GCP and AWS, where you have virtually no capex but relatively high opex.
And in the end, it really depends on how much you trust different vendors and how you want to manage cash flows. Racking your own servers reduces some risks (Google deciding to terminate your account on a whim, Azure pushing wild updates, Amazon jacking prices wildly) while increasing other risks (only your own staff are watching your hardware).
