My theory all these years was that I had children and no need of pets. It wasn't unusual to get home from work to find 10-12 kids doing crafts, listening to music, playing video games. I would feed them, help with homework or life skills.
Now I have 1 goldfish, 3 grandchildren, 4 honorary grandchildren (and 2 more on the way, and 10 nieces/ nephews. They all get spoiled!