A public company will have a board of directors who set the direction of the company; as such what is to stop the board from directing that the license be changed?
https://www.confluent.io/blog/license-changes-confluent-plat... https://blog.timescale.com/blog/building-open-source-busines...
I don't think there is any place for GPL in databases and similar software, specially if it is to be built and run by for-profit companies.
... then, most likely, Linux would never have taken off as contributors would have balked at the copyright assignment bureocracy, as well as not wanting to contribute to Linus's get-rich-quick scheme (why should Linus get special rights to profit of the work of the community?).
Do I misunderstand the copyright status of MySQL/MariaDB, or has MariaDB been clever about how it adds features to the GPL core, such that they're not legally derivative works?