That's sort of true, although in reality Airbyte was only truly "open source" for a very small period[0].

In reality, since about 1 year into the project, it's operated with a mix of open and "less open" licenses for different parts of the codebase, in a way that would make it difficult to just use the MIT licensed bit.

I think that kinda proves the point you were going for.

[0] https://github.com/airbytehq/airbyte/commits/master/LICENSE

It is ELv2 now, so definitely NOT open source. They lie about it on their website too.