Very interesting. No objections to your main points, but a few comments on side points and conclusions:

• You say "it's not like we know of a specific technological innovation that would solve poverty, if only someone would develop it." I would identify Greg Cochran's 'genetic spellcheck' as such a tech, along with what other people are suggesting. http://westhunt.wordpress.com/2012/02/27/typos/

• "We might have exhausted the low-hanging fruits in our desires." I think this is right, but it's complicated. I think the Robin Hanson way to frame this could be the following: innovation has been this rising technological tide that has made it a lot easier to meet most of Maslow's hierarchy of needs. But now most of the 'gains' from innovation are made in positional goods and services, which aren't the same sort of gains as, say, flush toilets, so they don't feel "real".