Paying for someone to manage the hardware is included in my assumptions. If you are asking "who would consider the role?" the answer is - Anyone who wants the money.
Who fixes Amazon's shit when it breaks at 3AM?
Who fixes Amazon's shit when it breaks at 3AM?
I know there's a threshold where the cost benefit works in favor of on prem, but it's nowhere near most 20 node k8s clusters.
Note that rented dedicated servers are 20x cheaper. What you're talking about, colocation, is 50x cheaper.