The bigger your system, the more compute and storage resources you’ll need, and this is independent if you host it on-prem or in the cloud. The advantage of cloud, is that you can more easily scale up and down, and you don’t have to plan this up front.

Now, limiting trending/retention/polling might indeed reduce the need for those compute and storage resources, but personally for me this is independent if you host it on-prem or in the cloud. You need to make reasonable decisions on what needs to be trended, how fast and how long you need all your data. And based on those decisions, this will indeed result in a hosting cost, but if you made the correct and reasonable choices, the cost will be reasonable as well. E.g. It doesn’t make sense to trend everything while you don’t need it, and it doesn’t make sense to trend nothing while you do need history on those key metrics. I would say, use common sense, and the hosting price will also be reasonable, on-prem or in the cloud.