it does, generally the deeper lithium ion batteries are discharged, the higher the likelihood of dendrites forming on the anode.

basically the more time that is spent not in the fully discharged state, the longer li-ion will last.

(this doesn't mean you want to leave it 100% charged either, that can also damage the pack; if leaving for extended non-use, leaving it at ~50% state of discharge is the generally recommended advice)

The disagreement is not with the science but with the idea that "because the company will have to honor more warranties, it is okay for them to charge more for features of the things they have already sold consumers". Maybe they should make less money, instead. Perhaps they can split the difference by amending the warranty to take into account the health of the battery. I don't really care! I (we. everyone.) hate a world where people retain control over things that they have ostensibly sold you and, predictably, scummily, attempt to extract more profit from them.

What if they did it the old way and simply never implemented a deep discharge mode in the first place? The product would never tap into the extra battery performance, you'd retain control over what you bought, and they wouldn't extract more profit.