Nonsense. It is important that the right type of dog be chosen of course. More than one is always good as well. A lot of the small dogs are really designed as  active  dogs (ratters). Farm dogs in urban environments are a nightmare: there's little worse you can do to a collie type than lock them up all alone in a house for ten hours a day.

On the other hand, hunting dogs were bred to put up with long periods of low activity so they don't get as worked up. For urban dogs, take a pair small hunting dog - say a dachshund - socialise them carefully, and you'll be fine. So long as you stick to dogs that still have a reasonable amount of sensible breeding in  them. Excessively bred show lines can be a nightmare. Having two makes sure that they're never left completely isolated from their pack.