Well Kiyosaki's latest posting is his recommendation to buy silver. Critics argued that gold & silver had under-performed against other metals, that precious metals were no longer relevant, that silver was no longer used in film...so his a total idiot. Well first of all, gold has doubled and silver done even better over the last few year despite the popularity of digital cameras.
2. How many industries can you get supply cost curves for each producer?
3. How many industries have terminal markets so they can sell everything they produce?
1. Mining costs have doubled in the last few years - not because of gold & silver mining but because the big iron ore, coal, base metal projects around the world hogged all the geological services and mine consumables, pushing prices up considerably. Well those metals will have softer prices in future because they are demand-based.