I don't know why that card is not labeled "RC", I know some cards say Rookie on them, but they're really not, but it's sometimes confusing for me too.
But I agree that there are way too many cards produced nowadays, between the base sets, plus the cyan, chrome, refractors, blue, rainbow, green, chrome rainbow, gold, gold chrome, gold chrome refractor, SN1, Chrome Printing Plates SN1, Chrome Printing Plates Magenta SN1, Opening Day, Autographs, Holiday, Artist Proof, Holograms, MEM, Relic, a player can get thousands of cards in just a couple of seasons.
It's insane! But it's just the card companies response to the demand of people looking to "invest" a pretty penny on that super ultra rare, SN1, PSA10, authenticated, certified, verified, genuine, bona fide, electrified card.
Good luck to whomever tries to collect every card from a player.
If your response to "Opening Day" is "for what?"... We cannot be friends.