As one Magic Twitter account slyly referenced in their obituary for the elemental ( Oh, and it draws a card. ), the elemental features a broad, explosive selection of payoffs, with zero drawbacks or requirements which would seem to balance it especially in a format starring Fabled Passage
Short version: its a ready-to-play 100-card Commander deck, mono-black, built around artifacts and recursion
The rise in general value of older Magic cards (especially those from Alpha/Beta/Unlimited or for cards on the Reserve List) has been driven by three sectors: 1
The Water Crystal Rating: 1/10 My Bruvac the Grandiloquent Commander deck is eating well with this set, but this isnt good in Limited
Magics current lead designer Mark Rosewater has a deep dive on these mechanics and their lasting influence on the game I highly recommend as further reading
Encore is one such ability from Commander Legends