Perhaps the misconception that bettas are "meant" to live in small amounts of water stems from the fact that bettas are usually sold in containers no larger than a teacup. Unlike most other fish at the aquarium store, bettas are extremely aggressive towards one another, and cannot be housed with other fish. Since they must be sold separately, they're put into cups and stacked row upon row to save room. Potential betta owners are then happily informed that the fish needs very little oxygen or water.
