THe issue is not so much that individual photographers can get an income stream for the rest of their lives, but that Bill Gates, who owns a gigantic library of images, can get an income stream for the rest of his life.
The technical writing books I write produce an income stream for those who pay my salary. Since the book's shelf life is about five years, copyright is not much of an issue, but if it were, I sure would hate to get paid piece wages for something that will remain a source of profit to Capital for the next century.
Joanna