No, they don't all leak. I have a 20 year old Jacuzzi that has never leaked. There are two main reasons that a tub springs leaks, either it's a poor quality tub or the tub has been abused chemically.
John
Or most commonly in my climate, they are improperly drained and left 'empty' during freezing season without being properly winterized.
We are here in Florida (near Tampa) so I guess the "freezing" does NOT apply, although we occasionally get a few days in our "winter" that the temps. may hit 28 degrees. I imagine that is when we would leave the circulator and heater ON !!