I think we could set the bar substantially higher. Don't even bother with discussion of sideloading. Talk about bounded transactions and device control.
What is needed is: Once I have purchased a device, the transaction is over. I then have 100% control over that device and the hardware maker, the retailer, and the OS maker have a combined 0% control.
What is needed is: Once I have purchased a device, the transaction is over. I then have 100% control over that device and the hardware maker, the retailer, and the OS maker have a combined 0% control.