Is it common for older dogs of small breeds to lose most of their teeth?

I contacted a breeder about adopting a retired dog (one that can no longer participate in competitions or be a stud dog). The breeder told me the dog is 6.5 years old and missing most of his teeth, which she claimed is common in small dogs of any breed.

Is this true? My knowledge of dogs is that of an average non-owner, but I was still surprised to learn this. These toy breeds typically live into their late teens but lose most of their teeth by age 7? How do they eat for the second half of their lives?