Market control is fleeting at best... easily lost in an afternoon.
Instead of trying to control a simple market, try spreading it out, it's less work and the rewards are as good. Albeit not as astronomical as the first few days if you manage to "control" a hot niche of market.
I don't see the motivation behind being 18+ hrs a day re-listing, undercutting, buying out competition, dodging the competence (yes you will need many alts for this, some serious AH pvpers have several accounts to spread their auctions and avoid being dodged) for virtual gold. You can manage to make 30-100k a week without investing more than 10 minutes a day in an average realm economy.
I have no problem competing in an open market, say for glyphs... but when someone comes in and tries to force everyone else out, I post 3 of all 406 glyphs at X-gold and leave it until they fold. It takes a few days and you may get some grief for it, but other sellers will understand when someone is trying to drive everyone else out. I cost a few gold to repost them everyday in 48-hour increments... that is well worth the price of watching the competitor fail and nerd-rage in trade chat. =)
Walling is the most terrible tactic ever imagined. It's crass and ineffective. Post normally, and don't post below cost. Paying attention to market crashers only masturbates their ego.
Will never happen OP, unless your server is really small.
I tried it myself, and it just never worked...Acepted my losses (10k gold etc) and moved on.
Well....to be honest, it can work if youre willing to spend alot off time for it (5 hours on AH a day atleast), and ofcourse you also haft to risk gold.
One reason for WoW decline I often hear is that its an old game and naturally people get bored with it. But TV is much older and people still watch that. Surely if a thing you once enjoyed keept staying fun, you would still use it?
Flasks: Bad Idea (reasons alread mentioned)
Magnificent hide: Works like a charm on my server. Farmes try to sell them, not many people know they can be crafted from 50 Leather. Still: They only way to get them is either farm or buy them from AH.
Back in Vanilla one guildie of mine made a "bond". You could invest into his bond, and he would give you a fixed interest rate for it. He simply needed a specific amout of money (20.000k) to control all of his desired markets. I don't think this can be done nowadays, because the gold supply is nearly endless and there are to many sources of the mats (like farm etc.).
With so many kobolds on ah this days it's impossible to control any kind of market...
Imagine for example glyph of Icy Touch... One of mandatory glyphs for dks... You and your competitors sell it fo 150-160 or even more... And then, kobold come and post 10 glyphs for 5g... U buy him out, repost, sell one of them for 200g, he shows up again, post 10 more glyphs fo 5g... You buy him out again, repost, sell one or two for 200g, and he again post 10 glyphs for 5g...
At the end, u have spent 100g to buy him out, earned 400g from selling 2 glyphs and got stuck with 18 glyphs u can't sell, because kobold keep posting glyphs for 5g and there's no market for them...
Or real example with gems... One kobold on my server posted 5 mystic sun's radiances for 15g... Regular price was 75-100... I buy his gems, repost at threshold, after 30 mins, he's back, posting 10 gems for 10g... I buy him up again, 30 mins later, guy is posting 50 gems for 3g each, even below vendor price... Raw gems costed ~30g at the time...
Most of ppl trying to earn something at AH don't have any idea how to do it so post stuff at ridiculous price and there's lot's of them, so that's reason why u can't control specific market...
With the lotus and flask market your best buy is stockpile, then dump your stock pile at the new undercut. Like on my server Lotus started backing up at 75 gold a lotus, but no one wants to charge less. You get a few folks that sell it at 60 and its slowly going down because people only buy it on the cheap because its readily available. Your best bet is take all of your supply and cash out and move to the next big market. If you don't know what that market is already, then you aren't ready to control even a small one like lotus. ie take 10 or 20 stacks of lotus sell them for say 50 gold a piece...a huge difference than the 68 to 75 they've been. take your 10 or 20k and invest in that next market. Basically undercut the undercutters with a huge flood of the goods and leave the market behind for the next one. Flask market is normally dead during T2, and should revive at the end of the expansion, T3 maybe this time, when everyone realized their stockpiles are out but are too lazy to farm them.
I have a hard time seeing anyone buying flasks at 300g each, on my server you get one flask for 50 gold no matter what sort, but i geuss it depends on how highly populated it is, being on one of the most populated horde realms in Europe though.
Market control can be achieved on smaller realms, as there is less factors which can affect your business, that would not be possible on mine because of how many people there are in the enchanting/jc and alchemy business, its a true babysitting market, i often get undercut by a copper or two within a minute of posting the auction.