Something to consider is how many applications depends on cutting edge database features. Developers often consider a database an object persistence mechanism whose details are to be tidied away. See, for example, the emphasis on database portability in ORMs.
MongoDB's most effective enterprise offering is support, in my opinion. They know their database well, which can make a big difference if your company is heavily reliant on it.
I suspect for many users though, AWS support will be good enough. Presumably, that's the danger to MongoDB.
You can bet that they don't care about some millions for development. On the contrary, it will help saving taxes.
Amazons behavior has been an amazing long-term, something many companies are thoroughly lacking.
IMHO, it's the need for single pane of glass management, coupled with single throat to choke accountability. Buyers are often willing to give up on best-of-breed features/performance/cost in exchange for simplification of process and workflow.
That’s kind of the point. If you want a managed service, Mongo can’t compete at the scale of AWS.
And by definition, if AWS is offering the same API, there is no “cloud vendor lock in”.
And even then they don’t host your database in your own VPC which is a big deal to some companies.