Assuming RDBMS is to be understood as ACID, this may be because of the need for more reliable hardware, and good IO hardware is comparatively expensive ? If yo

Assuming RDBMS is to be understood as ACID, this may be because of the need for more reliable hardware, and good IO hardware is comparatively expensive ? If you use things like mongodb and co, you are giving up on single-node durability, for example, and you don't need to have as much efficient IO (e.g. reasonable fsync performances). Otherwise, I don't see why mysql would require more expensive hardware mongodb