There's a lot -- and an increasing amount -- of knowledge that's specific to each cloud platform, and increasingly specialized (and complex) software. In the last couple of years or so I've definitely seen companies having to hire people to manage their cloud setups.
I suspect it depends on a lot of things -- the complexity of the project, its architecture, the development, maintenance and management practices. For a few years, me and a colleague used to manage a 30+ server setup without needing more than 8-10 hours a month. But we managed to pull it off not because of where the servers were, but because we chose a good and stable tech stack, we had the knowledge and experience required to manage it efficiently, and no one decreed that we shall henceforth move everything to the cloud because it cuts costs.
Given the same situation -- right stack, right experience, useful management practices -- I'm 100% sure you can pull off the same thing in the cloud, at least as far as efficiently managing the whole setup is concerned.
But IMHO the idea that cloud services give you all of that for free is snake oil. As soon as you need more than a virtual machine running a web server or whatever, what you end up with is exactly what you build. If what you build is crap, it's gonna run like crap, and you're going to need a crapload of money to keep it running, and two craploads of money to fix it.
I suspect it depends on a lot of things -- the complexity of the project, its architecture, the development, maintenance and management practices. For a few years, me and a colleague used to manage a 30+ server setup without needing more than 8-10 hours a month. But we managed to pull it off not because of where the servers were, but because we chose a good and stable tech stack, we had the knowledge and experience required to manage it efficiently, and no one decreed that we shall henceforth move everything to the cloud because it cuts costs.
Given the same situation -- right stack, right experience, useful management practices -- I'm 100% sure you can pull off the same thing in the cloud, at least as far as efficiently managing the whole setup is concerned.
But IMHO the idea that cloud services give you all of that for free is snake oil. As soon as you need more than a virtual machine running a web server or whatever, what you end up with is exactly what you build. If what you build is crap, it's gonna run like crap, and you're going to need a crapload of money to keep it running, and two craploads of money to fix it.