People don't realize how deep Amazon's hooks are at scale. We were dropping half a million USD a month at that successful startup I mentioned and could do the same work with four or five racks of hardware, storage included. I bet you could cut your opex in half on something else, and it's a safe bet because (a) I've seen it be resoundingly true even coming from three year reservations and (b) half is actually a conservative estimate. I am floored by how much money the industry throws at the fundamental inefficiency of multitenant virtualization atop AWS.
What a strange argument, considering Amazon a primitive. That's flirting with vendor koolaid. Physical and DigitalOcean/cheapo deployments are an immediate counterexample, too. Hell, if network latency is low enough, you can straddle both and schedule Kubernetes pods on whichever provider is cheaper on a given day. Spot instances, too. Lots of possibilities.