I can explain it further, as you all know there's an enchantment called "Fortune" Depeninding on "fortunes" level on the tool you have, you will gain more diamonds... And if you could buy ores at spawn you could EASILY make tons of diamonds and wreck the whole economy. Nuff said.
Hm, here is an idea... Since you can only have a maximum number of diamonds fall out of an ore (and other mats) from fortune, why not increase the amount needed to create a diamond ore? Needing 9 diamond per diamond ore would be fair, since I've never had more than four with Fortune IV. This gives people the opportunity to get the ore, without killing the economy.
This is a great idea. 9 diamonds for a diamond ore, 15 redstone for a redstone ore, 6 coal, and you'd need like 45 lapiz, since it can drop tons.