Lol this dude in your screenshot definitely has multiple accounts on this forum. I had the same suspicions when I was bidding on the q8 15%stance Chaos Axe for sale on here. Honestly, makes me not want to participate in bidding on these forums (for the Users that I notice this suspicious activity), because some of the sellers seem to be hustlers with multiple accounts to fuel their power sales to obtain more Arms for their $ supply.
Literally after 4-5days of no bids past my R/B, this "Famous Warrior" creates an account and bids on the Chaos Axe I'm bidding on, for an amount +5a higher than my R/B. (Which no worries, sellers rights and all). It got a little suspicious especially since the only post he commented on was the q8 Chaos axe thread. (kinda fishy for a new user to bid +5a over an already hit R/B; +1-2arms would be less fishy, especially since the seller had already posted that they'd be selling that day)
After he "supposedly" bought this q8 Chaos axe for the claimed 20a, he literally offers to sell me the axe for 20a (maybe 5mins after he bought it? lol). Who the hell is going to try to get rid of a collectors item for the same price they bought it, seconds/minutes after they bought it? I'm not buying that story.... sounds more like a way to get the numbers up to put pressure on actual people who are trying to bid on the forum.
He kept claiming that he's just a new user with a new account that hasn't played since like 2009 or some shit, and blah blah blah. He must have spent like 20minutes trying to get me to buy the damn axe, after I made it very clear to the Seller that I'm retracting all bids due to the "hustle" vibe I felt. I even made it clear to this alt account "Famous Warrior". Yet he kept trying to push it until I eventually ignored his ass.
Funnier yet, he kept trying to sell to some of my many alts in game, as well as fellow guild members, for that 20arm price. (Why the hell would a power trader sell an item that they just bought, for the same price?) This only makes sense if the Power Trader hasn't had any luck getting a return on their item after a lengthy time period...definitely a timer period greater than 1 day, yet alone minutes lol...
As to your actual question about Gold Selling...Kamadan, GToB should speak for itself for you, as well as Anets mass layoff months back. I'm sure there's still an occasional scan to rid some of the accounts, because no game developer is going to like the End User making money off of what they created. But, as there's no funding going into Guild Wars, the gold selling is definitely something that is here to stay in today's Guild Wars.
You mention that you just stick with trading cons, yet this is probably the biggest market of items that are botted (especially in Pre since you can convert the Pre BD for Post arms super fast thus making the cons give a lot higher of a return than if one sold the same amount in post). During the holiday week(s) events, these botters get characters full of cons to turn into black dye (if pre), or to turn into ecto/arms. They don't need the zkeys, because thats another hot item for botters. PvP is easily controlled with the lack of volume in activity in HA/GvG/Codex/RA (hence everybody selling Trims to guilds; there's no competition)
Multiple accounts = always have matches = always getting daily max zkeys on each account= always getting max boxes for each account
People with stacks and stacks of these boxes (especially the GvG and Codex) are dead give aways. You know how boring Codex and GvG is today (not including all monthly's for the few guilds that still play?). There's no way somebody is going to suffer through fighting AFK people, just to get their stacks of boxes.
HA at least has a bit of a activity, though with the same type of PvP players as well. A lot of the regulars may have multiple alts, and friends with multiple alts to guarantee consecutive wins.