What, you thought they'd all end up in a museum somewhere? Nope, they're ending up on eBay.
Seller tbhs575 has their hands on a number of the crushed, long-buried games, and among the stash are not just copies of ET, but also of Asteroids, Missile Command, Defender and Warlords.
Some are already going for hundreds of dollars. As you'd expect, given these are a part of video game folklore.
If you want to try and get your hands on one, remember, you're paying for the history, not the product: as tbhs575 warns, "The seller does not represent that this item is operable; it was buried for 30 years".