When you are an older cat you don't have a great desire for adventure anymore.
Older cats want to lay quietly around the house and enjoy the sound of the morning birds chirping (with fond memories of chasing them) and the warm embrace of their servants... the people of the house. Sometimes these people can get out of line, and when they do, they usually bring home a puppy.
But of course, if you're a kitten and you meet a puppy, you might not mind so much!
Not that puppies are a bad thing, they just tend to muddle things a bit.