Well, let me quickly explain why it is an issue.
It is really not practical to earn the money for a precursor through ordinary game play. You might get lucky and have the RNG Gods shine down on you, getting one precursor you can then sell to fund a large portion of the cost to purchase the one you do desire. However, the only way most people will be able to afford a precursor is to either buy the gold from a gold seller, or play the TP for profit.
People playing the TP for profit start small and build their wealth over time, being able to step foot into more and more lucrative markets as they go. Raw cost is not always the determination of most profit. A precursor may provide the most profit for a single sale, by far, but those sales can be few and far between. Active, hive volume markets can be very lucrative due to volume.
The higher the price of precursors goes, the more out of reach those items are to players who actually play the game, rather than play the TP. This drives more players to either buy gold from gold sellers, play the market for profits themselves, or just quit the game in frustration.
The goal of being able to afford the most expensive items on the TP, either for personal use, or as “an investment”, likely drives a large portion of inflation at all levels of the game.
The inflation we are seeing is largely due to the concentration of wealth into the hands of the few. Most players playing the game are not earning more money, they are just seeing the time it takes to earn the money to buy their leveling gear and level 80 exotics take longer an longer.
Inflation in the game is mostly driven by those playing the TP for profit, with the “market cap” increasing as ordinary players bite the bullet and buy things they need at higher prices and with longer intervals between purchases.
The highest price items just allow for those most successful at playing the market to earn more and more money doing so. Those players don’t stop playing and manipulating the commodity markets. They do, though, eventually reach an amount of wealth that allows them to easily manipulate the market on commodities and necessities.
The biggest hedge against such levels of manipulation was to be the “global” nature of the TP. Surely the markets would be too big to be manipulated by an individual? Well, goods selling for well over 20G have given them the mechanism for earning the wealth needed to eventually manipulate the global markets.
There a limit to how many orders a non-cheating trader can execute in a day. If the richest markets were ordinary exotics and T6 mats, that limit on how many orders a player could successfully manage would limit the rate of growth of TP “business”.
Precursors and other high priced items make levels of wealth accumulation practical that would not be practical otherwise. Don’t forget, they also provide the incentive for players to stop playing the actual game and start playing the TP, as well as for players to buy gold or pre-cursors from gold sellers. The highest price items fuel the behaviors that lead to inflation and these pressures can not be solved via ordinary money sinks, as those money sinks really only effect people playing the actual game, not those botting for gold or playing the TP for profit. It becomes a vicious, inflationary cycle.
You are mistaking increasing demand for rare items for inflation. Wealth consolidation does not cause inflation. Inflation is a measure of change in the value of currency (in this case gold), not the value of rare high demand items; it’s only really affected by the volume of gold in the economy, and the TP removes it. If enough players start playing the TP instead of the game it would eventually deplete gold stock in the economy, leading to deflation and a drop in price levels. TP trading only moves money around, it does not create it.
There are other factors you’re not examining too; if wealth were evenly distributed across the entire player base tomorrow, the cost of precursors would go down, but the cost of cheap and commonly traded materials would go up.