No, never, you'd have to be completely detached from reality to think that charitable giving could ever effectively replace welfare programs; it's a myth that the occasional deluded libertarian likes to spew because it's a comfortable lie that reassures their ideology, but it would simply not happen. Even if you could get people to donate a sufficient amount to cover the same money welfare programs provide (and, again, you couldn't), you wouldn't be able to guarantee the stability or the effectiveness of welfare programs designed to have a minimal impact on job seeking while ensuring a minimum standard of living for all people through stable, regular payments and services, and even if you could, the continued success of the program would depend entirely on the whims of a bunch of middle and upper middle class people, there would be no guarantee that the money that's there would be there the next month or year if you still need it. It's just an insane notion, and no reasonable person would think it could possibly be an adequate solution.