Most rocket folks purchase a commercial motor to launch. A small percentage make their own motors - APCP, Sugar, etc. The etc category is smallest, and includes Hybrids. Most folk just want to launch. For that majority, simpler is better. Solids are very simple when you aren't making the propellant.
Hybrids are intrinsically more complex to deal with than solids at launches. Solids are actually more complex to deal with for EX, if one ignores the hardware required for the Hybrid!
Commercial hybrids for the most part have hardware that is heavy for the total impulse, and have rather inconsistent performance being rather temperature sensitive. The first can be solved by using larger hybrids where the hardware mass fraction is lower. The second can be solved by various means, such as chilled nitrous as in my EX hybrid experiment (I'm not the first to do it).
Hybrids also tend to be long and thin (too much so really) and tend to need special purpose rockets. That's a big strike right there. Most kits are designed for motors no longer than the readily available commercial cases.
Most clubs, if they have launch equipment for hybrids, don't bring it out to launches. Many who have hybrids don't have their own GSE. That about ends it right there. Advertise some months in advance that you will have hybrid GSE set up at a launch, and see if people show up to launch hybrids. Not setting up for hybrids and then finding they don't show up? That's sort of obvious. But it is not necessarily an accurate gauge of interest!
Gerald