What's stopping Google from indexing single page Javascript applications? (theothersideofcode.com)

Regarding a recent discussion I've head in local dev community in Croatia regarding Javascript single page applications and SEO - there seems to be a great mismatch of where today's web technology is vs. where web crawlers are.

A discussion on what exists out there, what could be done and on which foundations could be found in there. Feel free to share your thoughts