Problem is, manufacturers sell on battery life, compact dimensions and so on. Toyota car batteries is the only commercial example I know of that substantially cut back capacity use in order to ensure longevity.
Edit: This is also why I find the battery life tests in phone reviews misguided. Raising charge voltages and maximising depth of discharge gives longer runtimes, but makes for worst possible battery longevity. Since reviews only considers and rewards one side of the balance, they actively contribute to development of devices with marginal battery longevity.
