There are devs releasing more consistent stuff with less money, less people and last but not least better quality. For example?
If they cannot manage to fulfill their promises, then better clarify that in advance to their patreons. Are there worse devs out of there? Of course, it's a long list, but personally I'm against the state of mind "Patreon=free money=do tf you want".
If it becomes a full-time job, as stated, then they'll have to work their asses even more on it, or at least inform those paying/supporting them. Then everyone can say what he wants, but on the long way people will eventually lose interest and later stop their support regards any kind of dev acting that way, unless they're masochist or extremely naive(or other adjectives).