One thing I don't understand is why Ambrosia never put their back catalogue on Steam. At least with EV Nova's Windows version, it seems to me that if you stripped out the licencing system and tossed it up on Steam, you could have had a nice income stream from there. I'd have bought it.
Most of the other games you might have been able to package into an emulator, like GOG games running in DOSbox.
But that's my outside perspective, so maybe there were bigger legal or technical hurdles?