You need to check the terms of the contract.
Clearly, if it's a 2-year contract it includes the price of the handset.
But UNLESS this contract says the price will be reduced by the end of the contract period, then it is up to the contract holder to re-negotiate at the end of the term.
You could move to a SIM only if you prefer. But sadly that did not happen.
It is not up to THREE to say, hey, do you want to move to a different tarriff.
I have a reminder in my phone every time my contract renews.
You could say the same with a Sky contract - the first one includes the box but later renewals do not.
The same principle applies here. It is up to the contract holder to re-negotiate the contract when the fixed term has ended.
I am sorry if this is not the answer you want, nor the one I want to give you, but I have a duty to be honest
Can I clarify anything for you about this today, please?
If you need anything further I am available for a follow up at no extra cost