Yes.
From what I understand (which isn't much) it's to do with the 'note envelope' produced by an acoustic double bass, which is more complex than that produced by an electric bass and is managed/reproduced better by smaller speakers.
That's the theory, in practice I found that 12s or, gods forbid, 15s can't reproduce notes below a B on the A string on a double bass very well, so that they all seem to run into each other and any walking bass line in that register is just undefined mush. With 8s or 5s, the notes are separated and sound much clearer.
Over the years I've played gigs with everything from 4x5s to 8x10s and I definitely prefer smaller drivers. If you need to be loud, then use lots and lots of small drivers.