Most animals avoid humans. More so in communities. Initially and perhaps for a generation or two people would still live in houses and buildings. There are billions of them. At least until they began to deteriorate and there were no more to live in. So they would have had shelter for quite awhile. And in time they would have adapted to being blind and found a way to function in the world. Blind people can do some pretty amazing things.They had an evolutionary biologist around and they were not able to figure out all the humans would be eaten and dead in a matter of months? They should have gotten a better evolutionary biologist.
Though, obviously, many would have died due to accidents, illnesses and such. I'm sure entire communities perished. Thus the low population. They only focus on a very small area so you don't know what the rest of the world looks like.