For an actress to be a success, she must have the face of a Venus, the brains of a Minerva, the grace of Terpsichore, the memory of a MaCaulay, the figure of Juno, and the hide of a rhinoceros.
I'm not sure why writing for others became harder. Probably a reluctance to give away anything you might conceivably use yourself caused a block. I did it, but it remained hard when it had once been easy.