I'll accept getting paid a small amount for my finished work, but getting donated and barely living off ZC work seems a bit unrealistic. You might just want to get an actual job and put yourself in a much more stable situation in life. Relying on others in such a obscure way is bad and can go pear-shaped regardless of your track record, it's frankly bound to happen. And what's worse is that said donations will pretty much crush any sort of creativity because in this supposed hypothetical situation, your donors feel more entitled to control your vision which is a terrible idea. Doesn't sound like a good investment to me at all, because then quest makers might be forced to go outside their strengths. Even a set of predetermined goals would be a much better idea.
I feel a lot of the "real life" stuff, are complex reasons. The userbase is young, so there are probably plenty of students putting their education first. Putting their work first. Putting their family and friends in need first. Money isn't some magic wand that will bring back everyone and increase the flow of quests, this community is too small to make a living, people outside the community will probably outright laugh at this idea. But I am all for making a quick buck if your quest is worth paying for in the far future, but that's yet to be seen... That will be fairly surreal to see, and ZC quests will need to put in a bit more effort to get there.