Although I come across Borges and Calvino fairly often, too, I have to admit that Gabriel Garcia Marquez is the only one of the other authors I am at all familiar with, so I am not sure which difference it might make. I would be curious, though, what that difference might look like to people writing about media art and architecture in Spanish, for example.

Based on the paragraph above can we conclude that "Gabriel Garcia Marquez is a writer."?
yes