Billy discovers there is a reason why the minimum is only 5k, because trying to make a sale in that spot is like trying to extract blood from a stone.
Trading guilds are open to all players, if you cannot make the sales required for minimal effort, then tough, if you do not want to participate in guilds, then that is ok, but the trading system does not merely work for high level farmers, naturally such a system does benefit them, but it does benefit casual sellers too, I myself only log on to do crafting writs on 14 characters per day and make a ton of sales too on top of that merely by selling excess gold mats etc etc.
The polls that periodically crop op on the forums are just a waste of space, it is not in any way indicative of the general feeling of the playerbase as most do not come here, much less care to post.
IMO, the ones who moan about the trader system make bad decisions on poor trading guilds, or have nothing of value to charge, some things are good money makers, like tri stat pots, gold mats, and other items, which have a healthy value over a long period of time.
I can only agree with what @Reverb says as well.