Online deployments are discussed with some frequency. Tooling is talked about. Always as a "cluster". Why do we need clusters anymore? Scaling containers, s

Online deployments are discussed with some frequency. Tooling is talked about. Always as a "cluster". Why do we need clusters anymore? Scaling containers, scaling functions, scaling, scaling, cluster, cluster. We suffer so much tunnel vision about horizontal scaling when it's just unnecessary anymore for most applications. The cloud products are all about horizontal. Do you really need more than the 400 threads >12TB ram with PBs of storage found in a reasonable high end server?