Usually, you rent a cage/room in one. For all practical purposes, it is yours. I went into a few of our data centers at my old job. There'd often be entire areas dedicated to spares, scooters, or whatever people visiting there might need.
If you can afford to run in the cloud, you can often afford 2-3 times your max capacity in a data center. People ended up in the cloud because it was less expensive. Now that the demand for data center space has decreased, running bare metal is less expensive by a large margin.
Combine that with Kubernetes and Harvester, you can basically have your own cloud at a fraction of the cost. Now you just need actual sys-admins instead of AWS experts ... and they cost about the same.
