The Steel Apron makes the wielder take -10 DMG from attacks and also safeguards it from Special Conditions (Poison, Burn, Sleep, Confusion, etc)
Resolve Lagrellas trigger first, putting Felidar Guardian back under Lagrella
Decks contain only 20 cards, energy generates automatically once per turn rather than through cards, you only need three points to win (with prize cards removed), benches allow for only three Pokmon, and card mechanics are simpler than modern Pokmon TCG norms
Play booster boxes are sold out most places, and the collectors boosters are pretty much only available from resellers at this point for extreme markups
Since it appears that there won't ever be another PSA 10 Pikachu Illustrator, it will take a lot for another Pokmon card to break this record
There likely are plans for ranked Expanded eventually, but as it is, Expanded is restricted only to casual matches, and does not necessarily feature the format's entire card pool