This is a fantastic summary and the only thing I would add is that FDB was publicly available only for a year and a half before Apple bought and close sourced it. There was simply not enough runway for the hype to develop. By the time it was open sourced again four years later, the world had moved on and FDB was something of a curiosity from the past, a what-could-have-been story.
> something of a curiosity from the past, a what-could-have-been story
This is what I find bizarre: one would think that engineers would take a rational approach and look at technical merit rather than follow hype.
Technically today FDB is state of the art, it's really hard to point to any distributed database that gives you strict serializable semantics and versionstamps (these are very flexible and a great tool to implement things like changefeeds).
But I agree that being bought by Apple killed the momentum and some people don't realize it's been open-sourced since.
