Virtually no open source project makes it big without some kind of full time commitment and/or corporate patronage.
However, there also isn't really any incubation mechanism in place for OSS. It sort of grows organically or it fades into obscurity, and that's not necessarily an optimal model.
The solution being that financial contributions early on might inject energy into a project which might otherwise lose steam. It makes sense to me. We've probably lost at least a few cool projects to atrophy-and-entropy land, which is a shame.