I mean that's what cloud is (outsourced server farm). Sure they also offer services on top, but that's mostly because they want to lock you in, and can charge more for, so it's a win win for them.
And there is no magic here, someone has to get the chips, build servers and connect them to network. And while they will often overbuild for capacity, they will never do it to a degree, where they can't run out, because that would be way to expensive and not financially viable.
I don't think any cloud will ever be able to guarantee to never run out of resources.
