Question

Perhaps you, a friend, or relative have been the victim of one of the recent cyber attacks at Target, BofA, or Citibank. Is it possible for businesses such as these to fully prevent such threats to your personal security or are they fighting a losing battle?

Answer 1

Theoretically, no.

All the defensive measurements, or precisely, precautions, are always passive with respect to new cyber attacks. 

In other words, the cyber attacks actually help the developer to know the bugs they have, and learn how to prevent when the similar attacks come again. 

It really depends on how you would define a "losing battle", but I would say, as long as the OS stays at the current state, they are fighting a battle that they will never win, but maybe the loss is not that huge.