People always say that such a thing will never fly in teams due to syntactic issues, but APL really is a productivity secret weapon for loners and small teams!
Following the same principle, R dplyr allows you to seamlessly interact with the DB by using a translation layer. However, every time I open R I find myself having to write tens if not hundreds of loc to shape the data where I'd do that in a few lines of J. For single researchers, it's actually much easier to read your one-page of J code 6 months later than it is for your 500-loc R script (again IMO).
Although I imagine it could be possible to really make a specialized APL geared towards data analysis as a strict DSL (APL is not a DSL). Meaning for example, making it more static and therefore statically compileable at the expense of losing things such as first-class environments (namespaces) or the "execute" primitive. One could also specialize the notation further towards statistics. There really is a whole realm of possibilities, here!
In a word, there is a market for lone scientists. It would be nice to have tools for that market ;-)
Commercial k variants come with a columnar data store (see Kx's q/kdb+, Shakti's k9).