Amazon was using MongoDB without paying for it. MongoDB found that objectionable, and changed the license such that Amazon would either have to pay, or stop using it. Amazon stopped using it, and started using its own in-house implementation instead (presumably because it was cheaper to develop it than to pay MongoDB). So, MongoDB got exactly what they asked for. It's just that, when they forced Amazon to make a choi…
Yeah, I don't understand it either. There is a company which puts 300 M$ effort into developing something and then another company is using the first company's brand recognition to get a competitive edge while offering zero added value (And no, hosting mongodb in AWS not a new thing, only uninformed people would assume so. When I look around I find services like Scalegrid or MDB Atlas itself which is exactly the thin…
Judging on your other comments, it doesn't look like you're familiar with MongoDB's historical shoddiness. I don't agree with you on practice in this case or any case. If MongoDB's company can't out-execute, then they should have never made their product open source to begin with (and in that case it probably would never have gotten as popular as it did). That's the bargain you have to make to try and monetize open source software -- you don't just get a business for free.
But beyond that, I don't agree with you on principle in this case, because I have nothing but disdain and scorn for MongoDB. Both MySQL and Postgres have fine support for unstructured data now, and provide the entire relational toolchest as well. That's not even getting into other multi-paradigm databases like CockroachDB or ArangoDB. I struggle to think of a use case that it is more appropriate for than another option; and indeed, every time I have had to deal with it in production, I have never thought that it was anything but a poor decision.