I'm probably not the best person to comment as I have seven! Apart from the very first who was an only dog for 3 years I have always had a multi dog household.
Well I've got 3 so I'd say yes. Dogs are a pack animal and try as we might to entertain and be company for them we can't speak dog. A dog with the company of another of its kind is in general far happier, there is the odd exception of course.