I feel like Rethink would have done a lot better if it were started closer to today. Funnily enough, in 2009 it was originally an SSD-optimized storage engine for MySQL.

The dev experience and API were great. It was the "relational mongodb".

Though no one feels daring enough to part from PSQL as a backend these days. With all the cloud deployment options and optimizations in PSQL, it's hard to justify writing your own db engine, but for a great real-time experience, that's what needs to happen.

Yes, and as a happy early adopter with many projects running off it, I was very happy about this. However the pace of development since then has been absolutely glacial and seemingly without direction. It's truly a shame.