Michał addresses his problems with relying on donations later on in the post. Dayjobs are the main source of burnout but devs need it to survive. It's very difficult for a FOSS project to get enough consistent funding to pay a liveable wage for even one dev without compromising on some aspects to gain funding. And even if they do, the FOSS work now becomes the dayjob and becomes a source of burnout. Ontop of this, donations are extremely unstable and there's no guarantee a project will be able to pay a dev enough every year.