"[W]e didn't open source it to get help from the community, to make the product better. We open sourced as a freemium strategy; to drive adoption." - MongoDB CEO Dev Ittycheria
Open source was never designed or planned to be used as "Gateway Drug" to move people to a proprietary locked in software, but more and more this is happening. This is not just a MongoDB move; Elastic, Redis, and others have all used the "Cloud" as a convenient excuse to erode classic open source licenses and values. At the same time new "open source compatible" versions of popular projects like MySQL or PostgreSQL pop up on cloud providers platforms. It's like the game "Among Us" only with your open source projects. You never know who or what is really open until you dig deep.