Whether they understand it or if they're just being impatient, individuals who buy the"purchase" skills are actually saving money and buy RS gold time by doing so. If they have the money to shed 200m on a skill, they obviously have a way to make money that is than to go accumulate 200m worth of materials. They've figured out it, although they may not be able to verbalize it. Paying the $10/month is just an expansion of that.
This would be really hard to'hide' from gamers, as sink tems can be identified almost instantly via GE data. It would be straightforward to develop an model to predict/identify them based on stuff like transaction volume and price swings. And id fully expect if that were to go as indicated sites such as'getracker' would include a tool on their front page suggesting these products. Why would you assume the items are being bought as the gp comes in or that they simply would not reveal trades completed this way as part of the trading volume considering its not.
It would not be difficult to conceal at all if they wanted to, there is an insane number of approaches. Simply because there's ways under all your assumptions around it does not make your assumptions right. I mean that the items are purchased from someone? Sell deals are being filled? My premise is that the ge tracker websites take information or at least in certain way that isn't data given from jagex although I could be wrong on this.
You are correct they could hide it if all information on sell/buy provides is taken straight from some API jagex has direct control over, and there's no other means of getting it out of customers, but I do not think that is the situation. Fundamentally there is of the methodology the strategy would take a version you can build. You understand that item is a sink item In the event the way more market offers are becoming filled for no reason. Then you are having no impact if you do not fill the market offers.
As yet another user suggested maybe the best way to fight this matter is simply get the things all at once (after the fact) but I think that might raise other potential issues like developing a weird risky marketplace based around sudden price spikes, where folks invest in crashed items only to get a chance their item will get picked. Then if it doesn't the item crashes. I guess if that is actually an issue people care about or whether its worse compared to cheap OSRS gold the current scenario is another argument.