...they're now rejecting work from many serious contributors that meets much higher quality standards than older files in the collection. They probably don't want to lose their 15m images byline - but it makes business sense (to me) to clear out the crap that isn't selling first and judge new work on it's merit...not because they have a glut of images.
This point has been made before and IMHO it is absolutely correct. And it is true of both photos and illustrations, and of other sites as well as SS.
If SS has 'too many' of a certain kind of image, such as icons (an example used above by Helix) then SS should go back and delete those old, technically crude images which never sell, instead of rejecting well-made new images, just because they are of icons. Buyers still want icons, and photo isolations, and so on. It is the old images which are the excess.
If Kroger has expired milk on the shelves which no one is buying, they throw out that milik. They don't tell suppliers to stop delivering fresh milk.
