I have learned the hard way that few people donate to support software (there are some exceptions of course).. And it can take a long time to build up a relationship with a userbase to the point where they know you are serious about working on the software and are willing to support it with their donations. And you have to be really up front about asking for donations. If you don't ask, and ask regularly, people will assume it's not something you care about.
I wrote an article touching on some of these issues
here.
But the bottom line is that if you think too hard about how few people donate compared to the number that download or use your software, you are going to get depressed and you may start to feel like you are being taken for granted, etc.
The only way to go forward with this kind of stuff is to work on these things chiefly for the pleasure of working on them and the reward of having happy users. We're just not at the place yet in the software world where many people are willing to financially support projects that they don't have to. Until that changes you just have to find a way to balance the time you spend on these projects with the time you spend making a living. It can still be a very satisfying experience.
I think part of the problem that you CircleDock guys have found yourself in is that you revived this project, and the two of you got so enthusiastic and energetic about improving it and making it better and more popular, at such a break neck speed, that you've found yourself on a path where the only natural way forward down the course you were on was to try to commercialize the program. 99 times out of a hundred in such a situation, you'd have written the program from scratch and you'd have the luxury to choose how to move forward with it. It's just that Circle Dock has a history and legacy that makes that path less viable, and that to honor Eric's project you have to honor his open source license and the restrictions that places on you.
I think mostly you guys need to just pause, step back a bit, take a deep breath, and reclaim some of your time and energy that you've been just exhausting pouring into Circle Dock work. I'm constantly surprised at how hard it is to get perspective when i'm deep in the middle of a project. You just need to take a break and clear your head and give yourself some time to figure out all this stuff and how you feel once you are out of the eye of the storm.
Everyone here at DC is wishing you the best in all things and is appreciative of all the work you've put in.