I can't imagine hitting a dog with my car. I hit a deer once and cried all the way to work. And the deer ran away, so maybe it was ok!
I truly understand where an owner would be heartbroken to see the story of their dog like this and not come forward knowing there beloved pet was getting the best care because there was no way for them to pay that bill. Many struggle today to care for their people families, let alone the cost of Vet care. Might be why the shelters are so full.