To a large extent this is true. But a lot of the complexity is introduced as a way to deal with the operational effort of running software (HA, security, platfo

To a large extent this is true. But a lot of the complexity is introduced as a way to deal with the operational effort of running software (HA, security, platform upgrades, backup/recovery, incident response, all that stuff). That doesn't mean it shouldn't be on a single server -- but a _lot_ of the motivation is preventing the dreaded 3am call.