They are multi-purpose devices.
An iPad used for watching movies whilst travelling might be hobbled by having little storage. An iPad that is mainly used in the home (as most are) for watching iPlayer or a bit of web browsing isn't so hobbled.
Indeed, it is that most iPads are used mainly on the home that means people are slow to upgrade them, hence slow sales (battery life isn't as crucial when a charger is always within reach. A newer, lighter model isn't as desirable if you're not carrying it around with you)
Biting the hand that feeds IT
