I don't understand why people believe that the price is going to be reduced later on. Everyone knew that the piano was going to be sold at a high price. You also seem to be ignoring that the items you're citing as examples were removed and brought back several months later at a lower price. Considering that the music shop only has only had the flute in the many months that it has existed in, I highly doubt that the piano is going to be removed from it.

You're not forced to buy the piano, there is a public one to use, and you can also play on other players' in their houses. Not a necessity, clearly a luxury item, and simply there if you want to purchase it.