> Oftentimes, I notice how pets (esp. cats[0]) are looked after 24/7 by their owners, groomed, given food, shelter, etc. and pretty much do nothing but continuously solicit pleasure.
Cats continually police the household to detect and eliminate vermin and other such pests, as well as acting as a deterrent to keep the pests and some other animals away. This function used to be more relevant in the past than it is today, however.
That said, I agree that cats are certainly in it to live a comfortable life. There's not really enough cognitive ability for there to be an exchange of comfort and labor, so humans just took advantage of cats' inherent nature. They require a pittance of food for performing a valuable service that humans struggle with doing directly.
These days, many households no longer require the services of a cat. In those households cats provide companionship. It might sound silly to compare the companionship of an animal to that with other humans, but unlike all relationships with humans, animals are nonjudgmental and always present and affectionate regardless of the circumstances. This might be the pets' adaptation to gaming the humans, but the humans nevertheless still find it to be a valuable service. There may be health benefits as well. I don't have any studies to reference, and I haven't researched the topic, but I've heard it mentioned a number of times: http://www.webmd.com/hypertension-high-blood-pressure/featur...
Describing cats as semi-domesticated seems accurate. They make eye contact and many cats are clearly interested in having a relationship with you individually (not all of them are aloof). They will come to you and meow for help solving problems. They're smart enough to "ask" you to open doors and perform other actions for them. But they don't really have a dog's attentiveness and perceptiveness toward the person, nor the dog's body language and subtlety of interaction. People like cats in part because they are independent and not needy. Owners don't need to worry about a cat going crazy if left alone in a house for a few days. However, I suspect that cats would score somewhere in between dogs and wolves on the tests mentioned in the article.