I'm pretty sure if I added 5000 images this year let alone increased my port by 6X my earnings would have gone up a little. At least on a few sites that seem to be selling new content along with the old. Can you find your images in searches?
My experience is things seem to be bumbling along at about the new normal - slow decline compared to 2017, down about 50% from 2012. 123RF has fallen off a relatively low cliff, SS doesn't seem to sell much new stuff at all, but no huge drastic across the board sudden calamity.