It’s not what you know but who you know.
Cynics say that when choosing associates we pretend to care about many things, but we mainly care about loyalty. Support comes from our apparently caring more for famously-loyal dogs than for lovable-but-aloof cats:
You’d think from the numbers that cats are "man’s best friend." … [U.S.] cats outnumber dogs by more than 10 million (82 million to 72 million). And, no question, kitties have legions of fans. But here’s the dirty little secret: Cats are more often neglected than dogs, more often relinquished to shelters than dogs and less often taken to veterinarians than dogs. …
"I hate cats" mail outnumbers the dog hate mail about 50 to 1. … Increasingly more cats are given up at shelters than their canine cousins. … An estimated 30% of those dogs who land in shelters eventually are reclaimed. Of the lost cats who find themselves in a shelter, a meager 2% to 5% are ever identified by their owners. …
Vet visits for pet cats have fallen 11% since 2001 … with more than a third of all cats never visiting a veterinarian in 2006 (compared with 17% of dogs who didn’t see a vet). … Morris Animal Foundation, a nonprofit funder of pet and wildlife health studies, is spending nearly three times as much on canine health initiatives as on cat health research.
Quid pro quo. That is it.
I would actually guess this has more to do with size bias. That is people generally value larger animals over smaller animals, which is apparent from the endangered and extinct animals which get the most attention and sympathy.
I would be interested in seeing the statistics for large dog breeds vs. small dog breeds. Do small dog stats look more like cats?