The fatal flaw with the current business model.

The only fatal flaw in Maple Story is people that spend thousands of dollars cubing items.

And thanks to that flaw, Maple lives.

Long live the flaws.

First of all, yeah I know your paradox is intentional.
I don't really care for the big spenders claiming that they are the only reason this game is still running, and that all us low spenders or free players are indebted to them for the privilege of being able to play this game.
Even the free players pay for this game. Up until some revamps of certain towns and areas contained certain NPCs like this:
Hey look a corporate advertisement. You just helped pay for this game with only your eyes.
Now, if you are running MapleStory right now, go ahead and close your client. Hey wow look a window popped up with an advertisement. You just helped pay for this game with only your eyes.

Nexon has so much untapped potential for implementing an ethical business model, but they continue to focus on their pineappleing pomegranatety cubes. Let's look at Evolution System. There's three cosmetic modifications that can be made: the map background, the background music, and the monster appearance. A wise decision would have been to monetize the Evolution System by just having the "free" option being just the default, and all of the cosmetic cores come from the Cash Shop. But Nexon is not wise. Nexon only knows one thing:

 Spoiler

We also recently received an update to our chat messenger system, and one of the included features are little icons you can include in your messages. A wise and profitable decision would have been to have all or most of these icons as Cash Shop exclusives, but once again, Nexon is not wise, and knows only one thing:

 Spoiler

Nexon may have people spending thousands of dollars cubing items, but how many people actually do that? Fifty? How many people has Nexon driven away that would spend ten dollars every three months? How much less ad revenue does Nexon collect because fewer people are around to see the ads?