From the angle I'm looking, AWS wants to sell Redis/Mongo/Elasticsearch because that's what the devs are using. The devs are using it because it solves one of their problems well (or, less charitably, because its a "standard part" of new-framework-de-jour).
I can't think of any piece of software that came out of a cloud provider into a place of being "the essential hot new dev framework".
I don't deny for a moment that Amazon/Google/Microsoft write a lot of software, but I haven't got an example I can point at of that moving out of their own ecosystem into the broader development community.