There are two things to consider:
One, clothing makes a difference. The corset she's wearing in that dumb commercial is like a metal push-up bra, so it's emphasizing what didn't need any emphasizing.
Two, some women actually have the equivalent of some animals' teeth for breast tissue...they never stop growing. I know of several women who when looking at pictures from their 20s, 30s, and 40s, show a consistent increase in breast size that would've required multiple world-class surgeries to do artificially in such a gradual manner and still appear even close to real. Yet in their cases you can tell by the "pancake" effect when they lie down that they're real, plus as they get older they're getting sag that fake ones don't.

So a gradual increase isn't unusual, being larger in your later years isn't unusual (especially if childbirth is involved, but even without), but the bizarre notion that large breasts MUST be fake is unusual.
It's like people WANT to believe they're fake, that being real is too good to be true or something. As it is they've usually got vapid personalities and a voice that shatters glass, why must they have had that surgery? Often you'll find they did have a nose job or chin lift or some other thing that no one guesses or comments on, but instead everyone harps on how what IS real is fake?



The Jedi Master