Cat behavior - instinct and learned

Cats have it pretty good around the Phactor household.  Kibble twice a day, lots of places to sleep, lots of nice windows, humans to provide some rubbing and petting when it's wanted.  What a deal.  Cats have a lot of hard-wired behaviors, things they do instinctively.  The younger of our two cats gets to venture outside at the end of a long leash, and she's amazingly good at stalking.  She drops and belly crawls forward, then freezes when the animal looks back, she uses the terrain for cover, and sometimes she gets surprisingly close for a cat on a cord.  Both like to play with things sort of hidden, grabbing for toys and the like, and not too gently either (fingers are not toys).  Both like to play with fuzzy toys, and the younger one plays really rough, a toy terror.  Both are fully armed with claws.  So last night and this morning some interesting sport arrived in the personage of a mouse in the house.  Oh, so very interesting. With the game so lop-sided, two large carnivores against one small prey animal, you figure this game isn't going to last long.  The older cat cornered the mouse behind a round garbage bin, and she moved as if she knew what she was doing.  But then the mouse made what looked like a fatal error and scooted for a safer place running right in front of the cat, right under her nose.  And she froze.  No grabbing it, no snapping at it, no pouncing!  What gives?  It was just as if she didn't know what to do.  The younger cat has reacted similarly.  After a stealthy stalk, she came nose to nose with her "prey", a youngish squirrel.  And she did nothing.  The game was over.  This makes you think that the stalking, the interest in the movement, and everything right up to the moment of truth in hunting is pretty instinctual, but neither of them knows how to kill their prey.  It's like their kitty brain gets up to the end of the hardwired behavior, and then their brain says, "Now what?"  So the mouse continues to roam the house.  Maybe it'll get chased to death, the cats like that part of the game, but it won't be dispatched by either of our cats actually attacking it to kill it.  The mother barn cats of my youth used to bring back almost dead mice for their kittens to "play" with, and it makes you think that the kittens had to learn how to kill their prey, an experience our pampered pets lack.  Or they just didn't want to sully the taste of kibble with mouse.