re: Why Space?
Space will become more affordable when there is a market demand. I have some hopes for tourism as an early market.
Resource exploitation in space seems far-fetched now, but things change. When oil was discovered in the Middle East in 1900 or so, nobody saw supertankers coming. A century ago, large-scale imports from overseas were a big deal. Now we routinely get even trivial things from places thousands of miles away and nobody thinks twice about it.
The nice thing about getting space resources to Earth is that it's downhill all the way.