I think some dogs do better in a small space than others. Greyhounds are large dogs...but they're sprinters and don't really need more than a couple of long walks a day. They sleep most of the time. Adult Great Danes are huge but they're lazy couch potatoes most of the time. A small dog might be able to run around and get all the exercise it needs chasing a ball in the living room. Some breeds are more independent and don't mind being alone. I think it's more a matter of matching your realistic lifestyle expectations with the needs common to the breed. There are definitely dogs who could be happy in an apartment or small space. Others might be okay if they got a lot of exercise or went to a doggie daycare to play while the owner was at work.