Does this really count as using boring technology? they're choosing the younger of the two DBs and to use some of the latest features e.g lateral joins
Funny, since you mention Postgres: 1996 is only PostgreSQL's first release. POSTGRES goes back even further [0]:
> POSTGRES has undergone several major releases since then. The first "demoware" system became operational in 1987 and was shown at the 1988 ACM-SIGMOD Conference. Version 1, described in The implementation of POSTGRES , was released to a few external users in June 1989. In response to a critique of the first rule system ( A commentary on the POSTGRES rules system ), the rule system was redesigned ( On Rules, Procedures, Caching and Views in Database Systems ), and Version 2 was released in June 1990 with the new rule system. Version 3 appeared in 1991 and added support for multiple storage managers, an improved query executor, and a rewritten rule system. For the most part, subsequent releases until Postgres95 (see below) focused on portability and reliability.
Your point stands, nonetheless. There are no whippersnappers present.
Postgres Initial release: 8 July 1996; 23 years ago
MySQL Initial release 23 May 1995; 24 years ago
1yr2mo difference. Not exactly earth shattering for a pair of projects two and a half decades old.