"I started on my server with only a rudimentary knowledge of the game itself and ipso facto zero understanding of its economy. Within six months or so, I had perhaps as detailed a mental model of it as one could get. I knew the price ranges of most of the items in the game and everything that all of them were used for. I knew how common they were on the market, who the major sellers were, what their supply chains looked like. I knew how fast they sold through, whether the price was stable or tacking a certain way, and I had tons of theories on ways to play all this to get what I needed and turn a profit while doing it, and nearly all of them were sound. Most of it I didn't even think about. I didn't need to contemplate why, for instance, lumber was both cheaper and more common than it should be, such that I could buy it all and hold, force the price up, corner the market, and keep it that way. I just kind of... knew, and did it. It's a wonderful feeling, weaving a system into your mind so tight that it's hard to find the stitches after awhile. Highly recommended.
[Closing paragraphs:] Eventually enough plugins updated for 1.7 that the admins decided it was time to update. This was known as the biome update, so named because it added dozens of new environment types and radically altered worldgen. Which meant that to take advantage of the new content, the server would be wiped, and everyone would start over.
In an attempt to prevent a repeat of the previous world, where a tiny clique of players achieved dizzying wealth at the expense of all the others, some measures were put in place to stymie our ambitions. An aggressive tax, scaling to multiple percent per day, on anyone holding more than a few tens of thousands of marbles. I warned this would backfire, that it would lead to pervasive hoarding and diamond as de facto alternative money, wildly distorting the market all to avoid taxation. This is exactly what happened: the price of diamond shot up relative to everything else, chronic shortages meant most players couldn't buy it at all, and those of us making big trades preferred to denominate in it rather than the official currency. I considered even standardizing a redstone contraption that would dispense a selectable number of items for every diamond inserted in, but never got around to it.
Once, when I wrote about all this in a different format, someone mentioned that online games don't necessarily have the same sort of stagnancy and barriers put up offline by entrenched, generational wealth. You can roll everyone back to zero and the selfsame people will get rich all over again. This is quite true. Part of it surely is many people don't like to play games the way we do. But much of it is you either have the time, skill, knowledge, and drive to work the angles and make your way to the top, or you don't. Making back our money wasn't just easy, it was trivial. Even with a leveled playing field, we raced ahead of everyone else. And then, one by one, we started to lose interest and drop off.
There's a skill curve to games like Europa Universalis where you start off bewildered by the multitudes of inscrutable systems laid out in front of you. Over time you learn to manage them, and the game shifts from something that seems to happen to you, to something you can participate in and compete with. But eventually you learn it well enough to find the cracks. With so much complexity, there are always oversights, always gamebreaking tactics, ways to grind the AI into dust. You have complete control over the game world, can effect any end you want. And then it becomes about building a story.
With Minecraft, with the economy, for us, there was no story to tell. There was only money.