The fatal flaw with the current business model.

The problem here, though, is that the TS didn't know.
What we have here is a very carefully constructed system of abstractions, layers of intermediary objects that displace the connection from the purchase and the gamble. The brain cannot accurately assess the situation.
We have, somehow, recently reached the point where we are no longer the ones playing the game. Nexon is playing us. MapleStory has mostly stopped being a skill game (as evidenced through many gameplay changes, including the redesign of many maps away from their original "platformer" style, and the introduction of many mobility moves such as double-jumps to virtually every class) and has transformed into a multiplayer money game. At this point, players enter a sequence of competitively spending money, upping the ante. There is no skill in an ante game; it's an endurance match. Players buy the win, and fight over it by outspending each other.

I don't understand why you believe now is when this occurred. This has been argued to death since 2011, even 2010. Ever since miracle cubes came out this has been a problem. At first it added some "Potential", unintentional pun, to customize your character to specific traits you wanted. But instead, they added something as ridiculous as a 9% potential stat increase. By the time it was released, players could easily break 80 to even 110% on their main stat. That's 1.1x stronger than any player by default. Super cubes just killed it off, with a whopping 12%, and nearly 8 additional slots, you were easily looking at a 300% stat increase.

Now in terms of "skill", I don't even think there was any in maplestory to begin with. But now all the classes are clones of eachother really, where the newly released class is 10x stronger with somehow, more mobility and sh`it like that. This formula has been around, god, 2009? When nearly every class got a variety of flash jump? I mean at this point, you're just repeating what I and other players have said for years, we even took action to change it and it just was flat out ignored.

There's a diverse spread of outcomes regarding how the players react, but let's focus on the most simple. As the ante game progresses, and the cost increases, an increasing number of players decide they cannot afford to match, and drop out of the race: either just the money game, or the whole game entirely. Some players just never realize they are in an ante game, or are somehow mysteriously wealthily profligate enough to continue participating enjoyably. And lastly, there are the gamers who quickly or even immediately detect the money game and become non-participants.
The success of this monetization tactic is entirely dependent on the target consumers being unaware of the money game. Since gamers who drop out do not just silently vanish, they become an additional, exponentially growing contributor to shattering the illusion, and their influence reaches not only those still are playing the money game, but also those who haven't yet started. Ergo, players are leaving and fewer and fewer players are replacing them. Eventually this comes to a toppling point, and it's all over from there.

This is an exhaustive business model; consumers are harvested until they are destroyed; there is no renew-ability. There is no sustainability.

We already reached the tipping point, the population that actually actively plays maplestory is merely a small portion what was. Most players either outgrew it, found out hacking was the way to go, got hacked themselves/unfairly banned, or lastly, as you said, couldn't keep up. Then you have the generation jump's, where some players will jump in randomly when new gear is coming out, and just invest and invest. They play for about 1-3 years, then the next gear jump happens, then you have a new generation.

The problem with maplestory is you don't actually ever stop upgrading, you could max scroll whatever gear, but the next generation, is nearly as strong at just base stats. That encourages players to go and invest into that gear. The problem with nexon is, I honestly don't think they understand the long term cost of investing into a weapon. It costs hundreds, sometimes thousands to get a perfect piece of gear. The problem they have is they see the money coming in, but these projects take months because certain scrolls are only released a limited time. So they never actually see the bigger picture.

Solution? Quit. Honestly, that's just what the game has become. You can sit here and discuss it, but you're 4 years too late, you can petition for it, but I can guarantee itll be ignored. The changes you and I want, aren't really determined by the NA branch, but the korean branch, so it's a fruitless endeavor. It didn't become this overnight, it gradually reached this nightmare point, and it's only going to get worse. If you have the patience/toleration to know that you may not be able to do everything, or not only are other players willing to cut your throat, but nexon is willing to abandon you at any moment, then that's your choice. But I feel as though players who choose that decision don't have a right to complain. This is common knowledge, it isn't some legendary treasure trove of information.