The leader is not just a card
Their beauty, with a spectacular foil finish and extended alternate art, limited availability of just 12 per set, and extreme rarity (about 1 in every 72 booster packs) contribute to their high value
Add to that the amount of Ruby cards with Rush, and Ruby's truly doing its job here (aka
Any cards that do not appear on TCGplayer or that do not have a market price are not included
While not repeatable in the same way Time Vault is, Time Walk doesnt require other cards or hoops to jump through to cast
This includes dropping the price on Masters set packs back down to $7, reprinting more cards that are expensive because they have a lot of demand (rather than cards like Imperial Recruiter that were expensive because they were low in supply), and refocusing reprint efforts to popular formats like Modern (either by bringing back Modern Masters or by making sure that themed Masters sets are stocked with expensive Modern staples)