"The unintended consequence of such potentially fatal levels [of alcohol] was her sudden and unexpected death,"
So says the coroner's office and so say we all.
This isn't dissimilar to what happened to Gram Parsons: he went straight for a couple of months , relapsed on heroine, tooking his usual dose and his body wasn't used to such a high level of toxic wear and tear any more and he OD'd.
For Amy, it is odd that such an addictive person would meet her end not at the end of a syringe but at the bottom of a bottle. Usually it can take decades to kill yourself from alcohol poisoning (trust me, I've tried and I'm still here) but the addiction had her so firmly in its grip it eat her alive.
What a sad story but not a waste: any more than dieing from cancer is a waste: in the end she got nailed by an illness.