Werewolf decks have been on the rise since the release of Innistrad Midnight Hunt a couple of months ago in many formats. The new Innistrad Crimson Vow set brought a few support cards for wolf and werewolf tribal decks as well.
Avabruck Caretaker is a great card, but it's a bit too expensive for competitive formats except commander. That's where it fits right into the Tovolar, Dire Overlord decks and that's the main reason why this card is being pushed in price.
Obviously, the price will be reduced after the initial spike, so expect it to fall to about $3-5 a piece.