Your concept is mathematically sound, but if there exists an opportunity to double dip to boost profits, what would make a corporation turn it down? As you noted in case #1, companies are paying much more for the materials. Consumers are still ultimately paying for it.

The entire point of amortizing the upfront costs is to keep the consumers hooked by charging a smaller recurring amount that stings less but certainly adds up to a bigger amount than the original upfront costs.

Besides, why would a company go through the added hassle of creating and managing a subscription model and risk pissing off customers through this nickeling-and-diming if not for more profits?

I am sure that there is still some silver lining to this scenario (e.g. I live in hot climate and don't need heated seats), but I fail to see any that apply to a broad number of consumers.