Not sure on the first. Apparently almost all alumninum is recycled, and reused, as its melting point is super low compared to most metals, so its not quite as wasteful as it seems at the first glance.

Why?

iPhones are iPads have a milled CNC “unibody” as well… Being able to dictate where to have more thickness helps a ton on the luxury feel. Most of the chips are recycled anyway into new billets.