I have a family member with four medium sized dogs. Their house is very well kept and clean. But the couch smells so bad. It's just dog. Dog all day. Ugh
My neighbor kenneled his dog and swept the house, and I came over to feed his cats while he was gone. The floor was somehow covered in dog hair again by the end of the week.
Yep, my roommate has a German Shepherd that sheds like crazy. He will sweep, vac, and mop and in a couple hours there's tumble weeds (dog hair) blowing across the living room again.
Way back in a former life I had a couch our labrador liked to sleep on, and it smelled pretty badly of dog. We got it stream cleaned at one point, which just made it smell of clean dog.