Windows Phone was killed by U.S. carriers that refused to activate them.
Naively I would think the SIM card functions as a sort of API to the carrier network, and as long as a phone supports that API, carriers should not know or care what type of phone it is. They shouldn't even know if the SIM has changed phones, so from that perspective, there should be no such thing as 'activating' a phone, only a SIM (though I don't know what exactly is meant by 'activating' in the first place).
Any deviation from this reeks of carrier abuse.
Performance and whether the network works at all is a holistic function of the base stations and all the phones attached to them. If a phone has a bad radio it could affect hundreds of other customers.
I still don't understand - what does 'activation' do, how does it prevent a bad radio from interfering with other customers? Why not kick phones with bad radios off their network, regardless of what model they are? Do they activate every phone with a conforming radio, or are they more picky? If they are more picky - why? How can they even distinguish one conforming phone from another? If a phone conforms to the network rules, what reason do they have for caring what sort of phone it is?
> and it is their right.
They are near-monopolies providing an essential service using public airwaves. Lets not pretend they're equivalent to Moe's tavern down the street.
A CDMA phone with bad power management could wreak a lot more havoc.