You are correct. Someone has to manage and plan the infra. But that is the same for on prem or other non cloud. What you don't necessary need is several database admins, several network admins, several kubernetes admins, etc. I don't necessarily agree, but that is the calculation. Azure hires the 24/7 admins for the service and you pay a bit more to get a share of them. I have heard this argument in person.

I think there is a very narrow space where you need the resources that this provides and it's not yet more cost effective to have your own team of admins. At a certain headcount a the number admins don't matter that much anymore.