You don't know, but you proved your customer's point, unwillingly.
The thing is, your logic is flawed because it's (incredibly) shortsighted.
> VMware, Xen, or Hyper-V admin
Those three things essentially do the same thing, yet they're completely different beasts. You have to look for people knowledgeable on that specific product, and you might not find them.
When dealing with AWS EC2 instances? A lot more people with standardized competencies.
For companies it's just great because they can hire from a much larger pool of candidates.
It's great for workers too, because they can pick my skills and go work at another company where I'll be immediately productive, meaning they'll have a much smoother onboarding process (learning the business domain rather than fighting the technology).
The main difference between cloud vs on-prem/colo/dedicated is that you need SRE/DevOps for the first, and sysadmins for the second.
My point was, financially and logically, it made (makes) no sense. It's penny-wise and pound foolish, given how (relatively) inexpensive a VMware, Xen, or Hyper-V admin is nowadays compared to anyone with AWS, Azure, or GCP credentials.