> Why isn't this a problem for other databases then?

It is?

- MongoDB went from AGPL to SSPL

- Redis went from BSD to SSPL

- Elasticsearch went from AGPL to SSPL

- CockroachDB went from Apache to BSL

- TimescaleDB went from Apache to Apache + TLS

- Graylog went from GPL to SSPL

> It's because the business model for ES is direct competition with AWS and others, and they got out competed. So they had to play licenses games to try and level the field.

That's why intellectual property law exist. If I spent years writing a book and you were allowed to copy it and sell it then obviously you're going to "out compete" me by default. You didn't incur any costs in producing the thing you're selling, duh!