I think the relative lack of a strong community around programmable music generation probably originates from a lack of a particularly good use case. To me, as both a programmer and an electronic music producer, applications like Sonic Pi and Supercollider are not all that appealing, and actually come off as downright tedious.
First of all, music creation is too chaotic a process to allow for simply getting things right on the first try. Single notes in arpeggios are changed, entire progressions are taken up and down steps, parameters are continuously played with until you find the right levels, and all of these and more are much better suited to graphical abstraction purely for ease of use. I'd much rather spin a virtual knob to find appropriate levels than type and re-type a variable quantity, especially if I have to wait for that quantity to update every time.
Second, music is all about edge cases. Using control flows to automatically change a piece is nice, but not as nice as quickly rearranging tracks in a visual playlist. Deciding that a particular loop should end in a different way is simple in a visual editor: cut off the tail and put something else in, or make one instance of the loop separate from the others and edit in place. These are processes that take less than a second for me, but would involve careful crafting of conditionals to achieve in Sonic Pi or the like.
All of that said, I think this approach probably has its merits. I've been wishing for scripting in DAWs for a long time, and having a synthesizer that supports writing code to modify waveforms or change how parameters link would be awesome (if this exists, someone please tell me). Projects like Sonic Pi, though, seem to take this past the point of usability.