Apple is under no obligation at any time to maintain your subscription because they too have the right to terminate the contract for iCloud and your Apple ID. If you get to the end of the billing cycle and they don't want you as a customer, they have no legal requirement to continue billing you and providing you service. Imagine how outrageous it would be to live in a society where sellers were prohibited from terminating contracts with customers who didn't pay them.

Moreover, you sign a contract when you agree to the terms of the purchase, as well as the trade in. None of this is a surprise.

Across the board, the author didn't read.