They shouldn't, that's why self hosted PaaS already do it for you, it's not a differential reason to use cloud services instead just because they do it for you too.

You don’t, you automate it. This has been a solved problem for literally years.

Now you have to maintain the automation. There is nothing wrong with that. There is nothing wrong with building your own server. There is nothing wrong with colocation. There is nothing wrong with driving to the colo to investigate an outage. There is nothing wrong with licensing arm and having TSMC fab your chip. There is nothing wrong with choosing which level of abstraction you prefer!