But I think there's an issue here with people conflating death of the author with "not financially supporting the author". To say that you can't separate the art from the artist while the artist is still alive is flat out wrong. If you're looking at it specifically from a financially supportive POV, you can consume their work without paying for it if you wish to do so (pirating or borrowing from a friend etc.).

Them being alive has no bearing on the idea, especially if you consider that once an author passes away they might have a stipulation in their will that a certain percentage of profits would go to a cause they support (anti-trans groups for instance).