If you purchase a server and stick it in a co-lo somewhere, and your business plans to exist for 10+ years — well, is that server still going to be powering your business 10 years from now? Or will you have moved its workloads to something newer? If so, you'll probably want to decommission and sell the server at some point. The time required to deal with that might not be worth the labor costs of your highly-paid engineers. Which means you might not actually end up re-capturing the depreciated value of the server, but instead will just let it rot on the shelf, or dispose of it as e-waste.

Hardware leasing is a lot simpler. Whether you lease servers from an OEM like Dell, there's a quick, well-known path to getting the EOLed hardware shipped back to Dell and the depreciated value paid back out to you.

And, of course, hardware renting is simpler still. Renting the hardware of the co-lo (i.e. "bare-metal unmanaged server" hosting plans) means never having to worry about the CapEx of the hardware in the first place. You just walk away at the end of your term. But, of course, that's when you start paying premiums on top of the hardware.

Renting VMs, then, is like renting hardware on a micro-scale; you never have to think about what you're running on, as — presuming your workload isn't welded to particular machine features like GPUs or local SSDs — you'll tend to automatically get migrated to newer hypervisor hardware generations as they become available.

When you work it out in terms of "ten years of ops-staff labor costs of dealing with generational migrations and sell-offs" vs. "ten years of premiums charged by hosting rentiers", the pricing is surprisingly comparable. (In fact, this is basically the math hosting providers use to figure out what they can charge without scaring away their large enterprise customers, who are fully capable of taking a better deal if there is one.)