It doesn't have to be C++ of course. The main point of OP lies in C++ being fast and easy to deploy (at least it can be). Go, Rust, to some extend C# and Java also fall in that category. This feature set becomes interesting, because it has the potential to simplify everything around it. If you don't need high fault tolerance you can go a very long way with just a single server, maybe sprinkled with some CDN caching in front if your users are international.
If you do need higher availability you can go the route StackOverflow was famous for for quite some time of having a single ReadWrite master server, a backup master to take over and a few of ReadOnly slave servers, IIRC. With such setups you can ignore all the extra complexities cloud deployments bring with them. And just because such simple setups make it possible to treat servers like pets, doesn't mean they have to be irreproducible undocumented messes.
If you do need higher availability you can go the route StackOverflow was famous for for quite some time of having a single ReadWrite master server, a backup master to take over and a few of ReadOnly slave servers, IIRC. With such setups you can ignore all the extra complexities cloud deployments bring with them. And just because such simple setups make it possible to treat servers like pets, doesn't mean they have to be irreproducible undocumented messes.