Unless, of course, someone improved the battery tech, making a higher-capacity cell of the same mass. Hmm. Improved battery chemistry? At Tesla? Could be.
But perhaps the improved battery chemisty is somewhat more expensive, so the new 75 kwh pack might cost more— and, at any rate, it will support a higher price point, since people will pay extra for extra range. So they charge more, either to keep up with increased costs, or to improve their margins (or both).
But losing the 60 kwh option will lose you some low-end bargain-hunter sales. They really want a Tesla, but they can only just barely afford it.
But limited numbers of low-end bargain sales aren’t enough to justify two different battery production lines, so they make just one 75 kwh pack, software-downgrade to it 60 kwh to scoop up the bargain buyers — but make it an easy upgrade for buyers who wish they’d bought more to start with, or have come into more money and can afford to upgrade. (As marketing data says they’ll usually want to do, eventually.)
So Tesla is minimizing its production costs, maximizing its unit sales, and improving customer satisfaction by making commonly-desired future upgrades easy.
What a horrible, perverse business model.
Demons! Demons I tell you! (-: