Unfortunately you need cashflow to build/sustain/expand anything.
Donationware can never, ever compete. It usually fades away when life events come knocking.
What works best is pay a minimal amount over many, many months. A subscription model. You just have to look how all top companies are incorporating this - it works.
The downside, and this is why Construct 2 is a pay it all up front model is that their user base are mostly hobbyists, who treat this as a hobby (wanting to go pro) but as all hobby's they are just that, and take a backseat the moment some crisis comes up (which happens often). Average user I would guess is a couple months. I said average for you veterans :)
Edit: What I am getting at is when you invest in a tool set, it is nice to have some guarantee that it will be around for awhile, and if you do change, it is because you choose to, and not because you are forced too.
Profitable businesses, tend to stick around. Cashflow is king, that is business 101.