Well, last I checked, they were still releasing Persona 3 drama CDs (which I have most of, despite not understanding them, for reasons that can only be explained by nerdy obsession). So, there's a good chance we'll see a fair number of these over a few years.
That's precisely my point, though---the Persona 3 drama CDs were released every month or so (with a break of nine months between the "Drama CD" series of three and the "Character Drama CD" series of five, but that's besides the point), while it's been over three months since this first Persona 4 CD was released. Oh well. All things in good time, I suppose.