Well this thread seems to have left the path that I thought it would travel, and take to the undergrowth alongside. It's become more interesting as a result, so please keep up the good work.

Referring back to the gold analogy, and the high cost of mining gold, there is an alternative form of mining for gold. This is often described as 'urban mining', and it is far cheaper. It also something that I enjoy if I get the chance. I look through the boxes at car boot and garage sales, and I hunt for broken gold watches, spectacle frames and other jewellery. I also bought a metal detector, but have yet to find a gold coin. It would be good if there was an urban mining technique for Bitcoin.