I think the simple answer is philosophy of Kaizen(改善)- continuous improvement. I started working with postgresql when it was just postgres95. Recently found that my earliest question on postgresql-users was 13th October 1998, 20 years ago (https://postgrespro.com/list/id/3.0.2.32.19981013214318.0069...).
I still use PostgreSQL in my startup for almost all critical production workload. This in itself a testament to its improvements. I remember I starting with c libraries of msql and postgres95 and continued to work with them as they evolved into postgreSQL and a new kid on the block mysql. I liked postgreSQL due to its adherence to SQL. Since I like working with relational algebra. So even though MySQL was more popular in later years, I still used PostgreSQL more often, except for building qmail servers with mySQL backend.
This might be valid if we were discussing an internal, proprietary software project.
We're talking about an open source project used by millions of people that has gotten CONTINUOUSLY better over the course of decades - to the point where it is now - arguably - the best of its kind.
Given this track record, I think postgres devs are entitled to use whatever management-speak euphemism they like. In this case, the idiom's original meaning/intent seems apt.
I still use PostgreSQL in my startup for almost all critical production workload. This in itself a testament to its improvements. I remember I starting with c libraries of msql and postgres95 and continued to work with them as they evolved into postgreSQL and a new kid on the block mysql. I liked postgreSQL due to its adherence to SQL. Since I like working with relational algebra. So even though MySQL was more popular in later years, I still used PostgreSQL more often, except for building qmail servers with mySQL backend.