Is it reasonable to consider an element of a device a consumable if it is not user replaceable?

No, exactly. I got a free battery replacement on my Macbook Pro after 3 years of having it because the battery was unusable.

After going into the Apple store, they said that the battery was a "consumable part" and therefore not covered by the warranty. However, when I asked what the part number was and how I could order a replacement myself, they said that the batteries weren't serviceable and even they had to replace the keyboard unit as that contained the battery and it was all glued together.

I pointed out that they've therefore designed this product to fail after a few years as you can't order replacement batteries as a consumer, and they agreed to replace it for free.

That is definitely an issue. I guess apple somehow calculated that an occasional free replacement is more economic than not binding the battery to a non-consumable part?

Yes, of course it is. Most users can’t replace tires, spark plugs, or even oil in their cars. Parts are considered consumable if they are reasonably expected to be consumed during normal operation. No court is going to hold a company liable for basic physics.

> Most users can’t replace tires, spark plugs, or even oil in their cars.

They don't want to, but they could with a 5 minute YouTube video and probably $10 in parts (plus the cost of the new tire, or oil, or whatever). Doing so also does not void the warranty on your car (maybe not true for spark plugs? Tires and oil can certainly be changed)

Umm, every user can replace tires, spark plugs, and oil on their car. If they don't want to do it themselves they can pay a company to do it for them.

No, but they might hold a company liable for intentionally suppressing the ability of any customer to maintain their products.

You mean unless you pay for a special policy? I think it typically comes with its own warranty. The replacement prices differentiate between in-warranty and AppleCare versus "out of warranty" price. Which seems to imply they do provide it by default, until it just expires.

They do state it is a consumable and that it should maintain a certain level for a certain number of recharge cycles. Of course not sure what kind of careful wording they were using pre-controversy. But obviously it should all come down to what they promise to be covering.