Maplestory "High Five" Private Showcase

Ugh, that stinks then. :\ they really should make these things tradable somehow. I really feel like they'd be the new mastery books and would be really good for the economy overall.

I absolutely hated the mastery book system and the way certain players and guilds, who "owned" the bosses that dropped certain books, controlled the market.
Then when the mastery books were changed so as to drop from normal mobs, botters profited.

And, as I said above, making the cores or core gemstones tradeable would mean that the meso-rich would have all the best cores, widening the damage gap further (as if removing the cap didn't make it bad enough already).
At least with each character having to get their own cores (can't even use your farming mules as Rebooters do for meso), the floor will rise evenly.

I agree with you that having everything in the game untradeable is a very annoying policy, and most of the time it's completely unjustified (or justified only by greed, see (P)SoKable items), but in this case I think it's for the best.