Land.
And Time. Time cannot be traded, but can be stolen (in raiding). Time is the main value item in TW. You can have Time without Land, but you will just be standing in 1 place. You can have Land without Time, but you will have cheap stuff. (Eventually, enough Land will offset enough Time. Re all the arguments about "the age bonus").
Time produces Gold. If you plant a tree or make a sap farm, Time produces Gold firsthand. No effort involved. Most of the other economies you mentioned require some other effort....weaving skill, planting skill, being a member, etc.
The present...economies...cannot exist without massive amounts of Land and Time. Some people have large quantities of both and fuel the upper end of the economy (or drive the inflation.)
Newbies usually have some Time but very little Land. Twisti hinted at the current model -- you either beg for Land (a parcel from a baron) or you hide out on some Land (but not a lot) or you steal some/raid.
But you still cannot really reach the higher end. Because the nature of the Time variable is that it cannot be caught. You can spend have enough Land to offset SOME time, but you cannot spend ANY amount of time and make 1 square = 24 hours of work. The exchange rate is much higher.
Driving Forces: to explore fun new content
Methods: Find land. Find dead base and inhabit it. Buy new content. Buy old character (buy Time) and get stuff. Be content with the content you have.
I don't think people whine...I think the game is nearly unplayable for noobs now. I've talked to some...I started a new character. The game is still addictive, but nowhere near what it used to be...and most of it us just because I know what is coming...I know the potential. And I'll never spend the time playing (with a new character) to get there. Expending 3 months of my time to get 4 new trees? yay. There are other games out there. I'm sure other people who "pass through" have the same idea.
(I have talked to quite a few people who have left the game...from god to newbie. I know why a lot of them left.

)
Community -- an interesting concept. Yes, there are a few people who talk on the fora and in "the channel". The group seems to change from epoch to epoch of tw history, but there are always some. Has the "active" base exceeded 100 yet? (Will it ever...?)
Clatra asked if the goal was to try to temp in everyone who plays. Based on this analysis (and reading the thread), I would say, "of course not". Twisti himself has implied that this is a hard game and not for whiners. A game for people who are willing to spend the Time and do repetitive actions over and over...even though the odds of their ever achieving some sort of personal goal in the game (like seeing the highest level tree from their own effort or getting ranked in the top 40) are miniscule. The game doesn't appeal to GAMERS...they are off shooting things. It doesn't appeal to casual players -- too little reward.
It does seem to appeal to macro writers.

I'm just sayin...look over the fora and see some of the biggest arguments. heh.
And think on this -- if all the OLD Gods..the old barons...hadn't gotten bored and left..would YOU be playing right now? How many people playing right now are playing because someone gave them land...money...stuff...?
I offer that there is a third element to the economy.
Land. Time.
And Turnover. People leaving provide a slow mulching of the TW soil.