Some ideas :

- the cat food business is control by mice
- no people to catch mice and canned them
- the best substitute would not replace the original product
- cats would not be hunting mice but sit in front of the shops
- no the smell of mice attracts the cat but the chase after it

Vet told me that if cat was larger it would not hunt mice but larger
animals. It goes according to proportions and the chase is the kick
they get not the mouse in particular as first choice for lunch, there is
also some allergies in many cats which eat mice and the instinct for hunting
could disappear.

Damn, it bothered me for long time. Now have satisfuctory info :)

regards