That’s why we need breeders of purebred dogs today. People who breed to preserve dog breeds are usually hobbyists. They may participate in dog shows or companion/performance events with their dogs. The dogs that they can’t keep are usually placed in pet homes. Yet cities and state legislatures are passing laws that can make it virtually impossible for smaller breeders to continue this important work.
You do not have to have own a large house to own a large dog (although a tiny apartment is not going to be big enough for one of the giant breeds). If you can take him outside for a good hour of two of exercise every day... a large dog can live in a small house or apartment just fine.
Every breed can be trained to learn almost every command. However, some breeds learn a lot faster than others - making them a lot easier to train. These highly intelligent breeds pick up a command after only about five or six repetitions, they more often respond on the first time you give the command, and they remember commands even if they are not practiced often. They also learn commands even when the trainer is inexperienced and makes mistakes. So if you do not have a lot of the time to spend dog training, or you are the impatient type who gets frustrated easily, choose a breed which has a high ease of training rating.
All puppies are cute, but some breeds have that extra “je ne sais quoi” that makes them irresistible. For this reason, some of these breeds are popular in greeting cards, commercials and other marketing materials.