I guess the answer is that it has become a business - I use the term loosely - for the very young who know not the days of the 50% deal. Digital is a red herring to the arguments surounding then and now: film and processing costs were never a problem to the pro user. Agencies used to copy the better shots (from those culled rigorously from accepted submissions, I might add) onto 4x5 and ship them all over the world to their branches and sub-agencies... And still make the huge profits that enticed Getty to buy in the first place!
I'm not sure that too
many professionals made a living from stock alone - I certainly could not - but it undoubtedly made the difference between a good year and a so-so one. And that wasn't a bad thing. And best of all, it even looked like it could one day be my second pension! Huh!