> This is certainly not the case with some of the herding / working dog breeds (GSD, Malinois etc) - it is borderline cruel keeping them in an apartment in some cases, and dangerous in others.

100%, I live in a city high rise. I see too many anxious dogs in that category that are "toys" to the owner and do not get sufficient exercise and mental stimulation. I love the beligan malinois breed but realize I have a lifestyle today that prevents me from owning one. Its similar to fish and aquarium sizes in many ways.