A lithium ion battery doesn't cost anywhere near that much, its either poor design and/or profiteering on the device manufacturers part to charge that much for a $15 battery to be replaced.
The battery is a user changeable part on most mid-range and low end phones.
The point of this predatory pricing tactic is to force owners of phones with sub-$200 in value to upgrade, rather than potentially waste half (or more) of the phone's value on replacing the battery.
Which carrier sold Android phones - where most users by their phones - have user replaceable batteries?
The Moto G is usually cited as one of the best mid range phone and it doesn’t have user replaceable batteries. I don’t think most of the cheap Walmart phones have user replaceable batteries.
I do about a dozen mobile repairs a year for family, and it really does seem like the new automobile.
Auto’s were not built for ease of repair, the repairs themselves can be quite easy if you know what to do, and often require components that are only 1 or 2 orders of magnitude in price. Paying someone who knows what to do with it, they also add an order (similar to screen repairs).
Also doesn't change the upstream clarification that you don't need to buy a new device to get a new battery.