@mia in the information age that proceeded electronics, stable psuedonyms were honoured by the name Nom De Plume.
The lot of the poor and women would have been the worse for it being prohibited, not to mention the lot of slaves.
Thinking of George Elliott, Maya Angleou, Current, Ellis and Acton Bell, Boz, George Orwell, Silence Dogood, Clive Hamilton, bell hooks, and Robert Galbraith, to give a few known examples. There were those whom we may dislike too Ayn Rand springs to mind.