Your assertion that if one makes a purcase of a ton of gold it won't affect the spot market price is patently idiotic, or do you remember what happened when the British stopped their selling in the middle of a sale of 35,000 ounces (that's about a ton)? Ashanti does! It caught them short on the options market and pushed them into bankruptcy (much to the delight of the British traders BTW).
There are thousands of products whose demand curve is flatter than gold. Try again.