I personally think that additions to the game like TCG make MS more interesting and more enjoyable to play.
Prices of items are ALWAYS going down, so if you bought that 10atk WG years ago, its worth a lot less now. When Leafre comes out, alot of the lvl 80-100 equips and weapons will be worth less because they will be easier to get once they drop from monsters other then like, Zakum or Pianus.
IMO, the only way Nexon could preserve the price of items is to NEVER add any additions to the game, which is a terrible idea. People would lose interest in the game fast.
And you could always buy your way to richness, either with Gapachon tickets or now, potentially with TCG codes.