Donations might not sustain us for the long term...but it's a start. We don't even know how much we need really right now. We should really get things started and get a better idea of how much we need. This thread is full of great ideas on how to get money for rewards. It might even be possible to roll any proposed changes into other hard forks, or together with updates.
But...it might not even be necessary to do a hard fork to get started. There's a lot of stuff that we need to do anyway.