> It's only cheaper if you're looking at a single purchase, not over time.
It's not entirely true, if you don't buy a new phone and simply live with a battery not holding power for more than a day, you get both cheaper price of the phone and a technically working phone.
Of course someone with higher expectations for battery time will have to buy a new phone sooner, but if you can't afford it, it's valuable to you personally regardless.
If the device degrades to the point where it’s effectively useless for my primary use case, I’m not really saving money. Useful timeline needs to be accounted for when considering cost effectiveness.
You are implying that the primary use case is the same for everyone. Consider this counter example: what if I want a phone to use a navigator app in my car (to leave it always on charge)? Battery life would not be important at all.
It's not entirely true, if you don't buy a new phone and simply live with a battery not holding power for more than a day, you get both cheaper price of the phone and a technically working phone.
Of course someone with higher expectations for battery time will have to buy a new phone sooner, but if you can't afford it, it's valuable to you personally regardless.