Why does nobody seem to have any introspection on why RethinkDB failed? Clearly there are some major problems that people re ignoring. If my favorite DB (I must mention Kx Systems once a month) folded, I could give you a laundry list of issues where things went sideways, but all I see is glowing praise and comments about the best tech not always winning (KDB knocks the socks off of everything, but I sure can give you…
I guess those other document-oriented dbms just had better early stage shilling to get funding before RethinkDB did, and by the time Rethink shopped around there was already enough competitors that investments in documented-oriented dbms dried up.
The current state of the art is an in-memory dbms to take advantage of future available (soon, 2017) non-volatile memory. CMU is developing such a dbms http://pelotondb.org/ and there's also MemSql and Sap Hana.