I feel your pain, Loren. The thing to remember is that abandonware doesn't suddenly stop working when the company goes out of business. Yes, you may need to keep an older computer in the studio to continue using these apps when they're no longer supported by your OS or hardware, but that's not the end of the world.
A couple of things, though, are a little strange to me.
First, why doesn't anybody make a general patch editor and librarian app for synthesizers any more? Unisyn was great, and Sound Diver wasn't bad. Can't some developer come up with a framework for people to develop and share their own patch editor interfaces? They wouldn't even have to individually support each synth... users would do that, using the framework, and could freely share the profiles.
Second, given that the Mac platform is so common in recording studios of all sizes, why hasn't at least one company come up with a top-notch app for editing stereo digital audio? Why is it that Sound Forge 1.0 from at least 15 years ago is STILL superior to any Mac OS digital audio editor? I've messed around with Bias Peak, Adobe Audition, TC Spark, Audacity, DSP-Quattro, and still keep going back to Sound Forge.
Speaking of DSP-Quattro, I thought the company had vanished but apparently they're back online again, and offering cheaper deals than ever on version 4 of their software.
http://www.dsp-quattro.com/dspquattro/Site/DSP-Quattro.html