In my place, when someone registers a SIM-Card and after using it for some times (months or years) they get rid of it either by mistake or intentionally, the network provider gives a duration of about 8 months or a year, if the SIM-Card is in-active for the duration of 8 months, it became recycled and sold to another customer.
My question here is, the way Bitcoin wallets are programed and being generated, is it also certain that old unused Bitcoin addresses (that was generated by someone but was not used or probably lost his phrase) can never be recycled by the system to be used again?
To my own understanding, Bitcoin addresses are generated through the private key/phrase of each wallet, and the same way two wallets can't have the same private key, an old wallet address can't be replaced no matter the duration of being inactive.
In the cases where a Sim is given to another user after months or years of inactivity, it's because of the need to manage storage space. The more new numbers generated, the more storage space is needed, so to manage storage space, they have to minimize the amount of new numbers being produced. That's why the policy of selling out old mobile numbers to new customers is being implemented. But the case of Bitcoin is different.