Why the Secret Spell Scroll system would have never worked.

They do, but you don't sell items for NX, you sell NX items for mesos or in-game items.

I see, so indeed the reason why we have such high inflation rate is the MTS since almost everyone wants NX (farm mesos, buy item in mesos, sell item for NX then buy other items with NX regarding mesos useless for most part) and just by buying NX you could buy stuff that would normally sell for mesos and with duping just making it worse.