Not being in part of core mean multiple solutions to fit different needs. Also a lot of people don't really need HA so it keep core feature more focused. (Again

Not being in part of core mean multiple solutions to fit different needs. Also a lot of people don't really need HA so it keep core feature more focused. (Again HA is supported at low level, you could totally achieve HA without third party, it just require more internal ressources) There are a lot of companies out there which provide enterprise support for PostgreSQL + HA.