The singular and sole purpose of the breast is to free newly born infants breast milk. They hormonal state of a pregnant woman makes them get engorged with milk. Men's predisposition towards breasts was inherently an instinct to look for key physical features indicating strength, health, virility, competence, child rearing, and child care. Wide hips and large breasts indicated a woman was capable of not only bearing a child without complication, but also be able to adequately feed them.
In many cultures around the world, woman's breasts were never seen as inherently sexual whatsoever. Thus woman were free to walk around in the open completely topless.
That quickly changed when woman's bodies were declared sacred by new religions. Then Woman started covering up due to the amount of rape that was happening because of invaders and colonists. Then again capitalist america started using woman as a prop or a gimmick for advertising products. Men would be memorized by woman with push-up bras that over extended the chest. Soon silicon injections and botox became the latest craze. Models adorn in name brand clothing would strut the stage at fasion shows with double D tatas, Actors on the set of the next James Bond Movie would be cast as the Terrible Two Timing Titania, Advertisements and commercials would plaster the walls and streets of America featuring the next big time product, introduced by Betty Bozonga and her huge Tomotallas.
It was not long before the ideology set in that a woman's value was tied to her tits. Now woman all around the world sought after methods of enhancing their chests, while men were completely brainwashed as well to be completely hooked on magazine after magazine of steamy centerfolds of Patty and her Perfect Pumped up Puppies.
It was the biggest craze that never went away. The universal obsession that swept the nation.