There is ongoing cost, sure -- that's why they don't stop selling new devices to interested customers, and making new versions of the devices to convince custom

There is ongoing cost, sure -- that's why they don't stop selling new devices to interested customers, and making new versions of the devices to convince customers to upgrade. If they need to justify the ongoing cost, they should charge an amount that they can amortize over the lifetime of the device -- if they expect to get $0.50 in ad revenue per year from each customer (which seems ridiculously high) then that means the device has to cost ~$20 more to support that, which I'm totally okay with. Maybe not everyone would be, but at some point you have to rely on the fact that you're not selling a commodity device; you're selling something that is better than your competitors, or else why bother?