PostgreSQL itself doesn't hire anyone. The trade mark is owned by the "PostgreSQL Community Association of Canada" (https://www.postgres.ca/), which does not hire people or engage in commercial activity. It's just there to protect the name.
There is a PostgreSQL core team (https://www.postgresql.org/developer/core/) that is a kind of steering committee, but does not make decisions concerning development. It consists of people from different companies.
The people who develop PostgreSQL are mostly hired by companies that have a commercial interest in the database and usually sell consulting, support, training, products that need PostgreSQL and customized closed-source forks of the database software.
There is no single authority in the PostgreSQL project. Decisions are made in mailing list discussions, cumbersome as that may be. The ultimate authority over the code is wielded by the committers (https://wiki.postgresql.org/wiki/Committers), which are highly trusted core developers who work for different companies. Development is slower than it might be with a single central authority, but that also part of the reason for the high software quality that PostgreSQL is known for.
There is a PostgreSQL core team (https://www.postgresql.org/developer/core/) that is a kind of steering committee, but does not make decisions concerning development. It consists of people from different companies.
The people who develop PostgreSQL are mostly hired by companies that have a commercial interest in the database and usually sell consulting, support, training, products that need PostgreSQL and customized closed-source forks of the database software.
There is no single authority in the PostgreSQL project. Decisions are made in mailing list discussions, cumbersome as that may be. The ultimate authority over the code is wielded by the committers (https://wiki.postgresql.org/wiki/Committers), which are highly trusted core developers who work for different companies. Development is slower than it might be with a single central authority, but that also part of the reason for the high software quality that PostgreSQL is known for.