Voici la réponse de Gail Carriger, l'auteur du Protectorat de l'ombrelle.
Pour lire la réponse d'autres auteurs, c'est sur le site SF Signal.I have many theories on this. Part of the appeal, I think, has to do with our own sense of chaos and impending doom. This often causes people to look back and seek out a time that was feels more ridged and controlled, full of polite manners and structured forms of address. It's a way of escaping into formality. I think that is a large part of steampunk's charm.
Steampunk is also special as a movement because it isn't entirely literary - these days it has ties to the green movement, the maker community, historical reenactment societies, musicians, artists, and the fashion world. I believe any aesthetic component lends to escapist appeal. With our economy in chaos, steampunk offers up an alternative lifestyle of sedate civilized behavior and beautiful dress.
I suppose I believe steampunk has persisted because it has evolved to being more than just a literary movement. All great ideas eventually become larger than the sum of their parts, if we are lucky, steampunk will continue to do so.