I’m not sure what you mean by "not distributed". With kdb+ you have a lot of flexibility in how to setup the database. You can organize the data to be stored in a distributed fashion (across multiple devices, multiple servers), you can setup query load balancers to distribute work-loads, and you can replicate to multiple servers/devices. You don’t have to use K, you code in q, which most people find far easier to read/write. There’s a wealth of information to help with all this[1], and a very responsive user group.

But yes, you do need kdb+ expertise to get full use out of the tool. And yes, feelings seem to run strong towards kdb+, in both directions, love/hate it. And correct again, it’s not free and the licensing cost is definitely a hurdle to wider adoption.

[1] - http://code.kx.com