"Concerning asteroid material: it is extremely expensive to get to an asteroid and we are nowhere near able to extract specific raw material from asteroids (there are no mineral ores in space); these problems add to each other. "

Well, if you only need a relatively small amount of material from asteroids. e.g. If there is now, say 1 trillion tons of relatively pure platinum ore in the asteroids, and all you "need" is a million tons of platinum ore. Over the course of billions of years one could have say a billion tonnes of platinum ore bearing asteroids impact the Moon. 99.9% those impacts could have vaporized, but if .1% impacted at a slower velocity [the slowest possible is lunar escape velocity] then you could have .1% of a billion tonnes [1 million tonnes] of relatively intact platinum ore.

Now, suppose you could find 1% of the million tonnes on the lunar surface- 10,000 tons. Or 10 million kgs, this could be enough to start mining, with possibility of finding more of them on the lunar surface at a later time.
A sphere of ore with density of 5000 kg per cubic meter is about 16 meters [50'] in diameter is about 10 million kgs.

1 kilogram = 32.1507466 troy oz

"Platinum prices rise above $2,000 per ounce in New York"
Wednesday, February 13, 2008
http://www.metalmarkets.org.uk/2008/02/13/platinum-prices-rise-above-2000-per-ounce-in-new-york/

So, say 5 million kgs of platinum at $2000 per troy oz is worth 321.5 billion dollars.
Could you spend say 100 billion dollars to mine and return it to Earth?
If you could it would be profitable.
How you did it would depend on many factors- maybe you would want send the ore back to earth.
Some people might pay more for lunar platinum ore than compared to the commodity price of the platinum you extract from it. Some "natural" lunar platinum ore might make good jewelry or nice a paper weight- more valuable per gram or caret than diamonds.

"The oil industry reached very cheap results thanks to years of use, huge markets and huge dependancy."

I love how we are dependent on something little valued at one time. We dependent on oil only because it is cheap- even at $100 per barrel oil is cheap- that's cheaper than orange juice and orange juice is fairly useless compared to crude oil.
Ever wondered why a million barrels of crude oil "spilled" is considered less than having any value?
Consider the possibility that it's possible that oil isn't "spilled" enough for there to be enough market for it's recovery.

Anyhow, crude oil is a product with many uses, gasoline is important if you don't like walking for miles, and Kerosene is nice if you want to fly.