Just a note before people start getting confused. Profit and loss analysis is different than supply and demand. Time spent doing an activity is calculated via profit and loss, market fluctuations are supply and demand. Just like someones boss will set a wage for a said job those decisions are based on profit and loss analysis, just like people choose to craft or choose to camp/farm or both. The market selling prices are based on supply and demand. For instance just over a year ago most NIN tools were cheaper on the ah than the NPCs but now they are inflated because there are far more people buying tools it is not just the 1 type that has risen drastically.
Both the ingredients and finished product for shihei are low level synthesis. If you don't believe 100-150k is worth a few hours of work then level the crafts to make them for yourself it will only take you a few hours to get them to that point then you can have no reason at all apart from laziness to complain about the price.