Thanks for putting this into words.
Few people understand the time, effort, and dedication involved in creating a viable fork that will last. Unless someone is sitting on a bunch of free time that they can continually throw at a thing, it doesn’t make good sense to fork something of more than a couple hundred lines. It’s too much work for no return.
It’s nice that a few people have expressed interest in purchasing premium versions of plugins, however, I think the developer is still faced with the same issue: the ClassicPress userbase is too small to expect more than a couple purchases per year – far too few to support the effort. That number is just a guess, of course, however, I feel it’s an accurate assumption as I’ve released about a dozen free plugins in 18 months and still haven’t managed to get up to 100 (cumulative) installs yet.