> I believe partially due to vendors getting their hooks in decades ago and expanding scope and increasing prices I would be surprised if this isn't the vast m

> I believe partially due to vendors getting their hooks in decades ago and expanding scope and increasing prices I would be surprised if this isn't the vast majority of it, with the rest being the over-provisioning you mention later. Mostly, it's tough to gauge, because each effect is multiplicative. I'll go so far as to say that, somewhere between 10 and 15 years ago, that any hardware support you've been paying to vendors can be considered as complete waste [1]. Worse, it's often a percentage (i.e. multiplier) of original purchase that goes one indefinitely, even though the value of that gear falls rapidly. Also, (for that 90% you believe you can move to the cloud), if you have any proprietary hardware, you're paying an eye-watering multiple of its commodity equivalent (even considering additional labor, if any). The above is easiest to observe in storage. There's not all that much mystery around how much the components cost and how reliable they are, so cost estimation for an equivalent commodity solution is easy enough. Today, even commodity/free no longer means "no frills" in terms of software features, but I expect that's less relevant when comparing to cloud providers, anyway. > you wouldn't believe the savings, or maybe you would, which is even more when not ported 1:1 but used in conjunction with smaller VMs I very much would. Just remember you can smaller VMs yourself, cheaper than cloud providers, bringing your staff up to speed on more modern skills, so long as you don't fall into a vendor's trap. VMWare's model where the software ends up cost is the same order of magnitude as the hardware is such a trap, but so is software that's free but requires expensive professional services to set up and maintain (OpenStack, historically, though I'm not sure if that's still true). > and autoscaling. This, actually, is the rare case where cloud providers can save really save money, if your duty cycle (for lack of a better term) is under 10% of so. Other comments in the thread mentioned this, as well. Unfortunately, if you never autoscale to (approximately) zero, then you're grossly over-paying for that base load, which can wipe out those savings. The "hybrid cloud" model addresses this, as well as avoiding all-or-nothing thinking. Ultimately, if you're optimizing (not necessarily exclusively, of course) for cost and want it to last, you'll have to change the whole organization's way of thinking. Avoiding vendor lock-in is key, be it proprietary hardware, software, or cloud providers. Also, encourage good engineering practice/culture, without getting overly focused on the latest fashionable tool. (A trite example being saving on labor through automation but buggy automation causing an eye-watering AWS bill). [1] There's some non-zero value to any actual replacement hardware, but that's negligible if considering what you actually got, net of any markup for being propreitary.