"Tiny toy" is a term that is only used by a breeder who is attempting to profit off of her dogs, not breeding to improve the breed. By attempting to breed the dog with size as a primary concern instead of health, you will inevitably have dogs that are less healthy than their counterparts.
This doesn't mean that the size of the dog directly causes the issue, but that the quality of breeding is affecting it. Smaller dogs ARE more fragile than larger dogs as well.
Someone who purchases a "tiny toy" animal may have their animal live just as long if not longer than a toy poodle bred properly, but on average I would wager that the tiny toys will not live as long.
You could essentially ask "Do BYB/Puppy mill dogs live longer or shorter life spans than well bred dogs" and come up with the same answer for the mostly the same reasons.