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…
You're just talking narrowly about Amazon in this comment. What you said makes more sense if you broaden it to commercial users. They might have known FAANG companies, esp Amazon, would just ditch their software if they switched licenses. They might be targeting the companies that can't or won't build a MongoDB knockoff. The companies that will actually pay for their product. That's a huge market.