MySQL never changed its license. The fork happened due to concerns of ownership and direction, not a license change or "going too commercial".
MySQL is still widely used, including by a large portion of publicly-traded tech companies. That said, most newer startups seem to be choosing Postgres instead.
MariaDB is also somewhat widely used, but not nearly as much as MySQL. And MariaDB's commercial enterprise (which was VC-backed and went public via a SPAC) is not doing well.
Your belief is incorrect. The links you have provided do not provide any data on actual use of these databases in the industry.
I've been working in the MySQL/MariaDB ecosystem for 21 years and am the creator/maintainer of a MySQL and MariaDB specific schema management utility used by hundreds of companies and with over 1.6 million downloads to date. I can tell you conclusively, MySQL usage in the industry significantly exceeds MariaDB's.
While I personally enjoy both systems and do hope MariaDB adoption increases, this doesn't change the facts on the ground. And unfortunately MRDB is a penny stock, Azure is dropping their managed MariaDB offering, Vitess has dropped MariaDB support entirely, AWS Aurora is compatible with MySQL and not MariaDB, Percona Server is based on MySQL and not MariaDB, and so forth.
I'll defer to your on the ground expertise as to the relative popularity of each, but I will point out that we're both working with anecdata here. I might also suggest that MySQL is losing a lot of ground to Postgres and I don't expect that trend to reverse in any case.
In any case it's not very relevant to this thread because you're quite right in pointing out that MySQL uses a free software license (GPL).
Yes, I mentioned the losing ground to Postgres aspect in my original comment. But that affects both MySQL and MariaDB, and still does not cause MariaDB to somehow be more popular than MySQL.
As for both working with anecdata, I mean sure, but what else is there? I'm citing my own business's direct experience with MySQL users and customers significantly outnumbering MariaDB users and customers, and seeing clear signs of that trend also being true at several much larger businesses (AWS, Azure, Percona, PlanetScale).
I suspect your view may be skewed by Linux distros / package managers having replaced MySQL with MariaDB many years ago. But even that is starting to change, see https://lwn.net/Articles/960630/ for example.
MySQL is still widely used, including by a large portion of publicly-traded tech companies. That said, most newer startups seem to be choosing Postgres instead.
MariaDB is also somewhat widely used, but not nearly as much as MySQL. And MariaDB's commercial enterprise (which was VC-backed and went public via a SPAC) is not doing well.