Hi, that was me.
There wasn't a fundraiser, just a thank-you card for jwe, Octave lead dev. We get some money from FSF donations but not enough to support a single dev. We mostly use the donation money to pay for travel expenses for the yearly Octconf.
I used to have an Octave job, but my current job is unrelated to Octave. I've been trying to court Enthought and Continuum Analytics to try to hire me or any other Octave dev to work on Octave again. My pitch is that while moving people off Matlab is a laudable goal, there's a lot of Matlab code out there that could be used as-is while they write new code in Python or Julia or whatever. With stuff like Pytave that glues Octave and Python, Octave could help their customers transition off Matlab.
I have personally been affected by more than a couple of ghostscript bugs that have drastically impacted my use of Octave over the years, either crashing, busy waiting, or memory grabbing. My first response has always been to start digging into ghostscript to find out why it's screwing me over and try to fix it myself or come up with a workaround.
Not making an excuse, just offering that for myself one of the immeasurable advantages of working with completely free software is that I feel empowered to at least try to identify and fix problems when they happen.
In the cases you mention, surely it would be trivial to prove if the problem was Ghostscript or not by demonstrating graph 3 or the missing data points were output or not by Octave before Ghostscripts png conversion.
Surely modularity makes it easier to isolate bugs to a module ?
Were these bugs fixed ? You should go back and see.