I always laugh hysterically when I see sellers who think they have the right or even capacity to dictate prices in a free market, ESPECIALLY in an MMO.

Supply for goods in MMOs is always increasing. Always. Every day there are new crafters/gatherers able to produce the same goods as you; there's no such thing as branding, every item can be guaranteed by the fact that it's a video game to be identical in quality and function. Therefore, every new seller on the market is absolute competition, and the only meaningful distinction between sellers is their price points.
Prices are set as a factor of quality, material cost, labor/logistics cost, tax, and other surcharges (e.g. branding)
We already know that quality, tax, and material cost are fixed for all sellers, (HQ vs NQ notwithstanding, as they are effectively different goods) and the thing that I think trips up most sellers who complain about undercutting is that labor has no real value in this game. SE is not providing you with subsidies, there is no minimum wage, and 99% of all sellers/crafters are NOT hiring other people to produce goods that need to be compensated. Your labor has only the value of what the market gives it when buyers/sellers decide to price goods. The sellers that get all upset about undercutting have some magical idea in their heads of what their labor is worth, have tacked on some artificial value on top of that as their desired profit, and then get butthurt when the price point starts cutting into what they think are labor costs.

Here's a hint: the open market will not give even a moment's consideration to what YOU think your labor is worth. If some other seller is okay with charging slightly less because they think that's still a fair price for their labor, there is not a damn thing you can do about it. Especially because this is a video game, where material supply is limitless in all but the most niche of instances, (time-locked materials like Platinum/Glazenuts, artificially limited goods like Demimateria/ventures, etc.) market prices for finished products will ALWAYS slowly drift down from the inflation of new content releases until they bottom out at material cost + a small margin. This margin is dictated by the number of SELLERS willing to SELL at low labor costs, so the size of it tends to vary by the rarity of the product, but the point is that having large margins will never ever be sustainable. The sooner you get that into your head the more profit you will make.