"Necessity is the mother of invention" - old adageBasic economics has always indicated that there would be industry no change from v4 to v6 until it was necessary, and the only real necessity for doing so is the exhaustion of IPv4 addresses. So I don't think that the lack of industry deployment of v6 until now should be a surprise, and neither does it mean it has "failed" - I believe it has been simply a case of waiting for the right time, and that time should be from the RIR exhaustion over the next 12 months.
Nothing would drive IPv6 adoption faster than useful content only being available via v6, which would force customers to demand their (internet and application) providers make that content available somehow, driving the providers towards v6. Of course, it is too soon right now to make content IPv6-only, because an insignificant number of people would be able to access it, and therefore its availability could never be known by the general Internet community.
But if content providers are able for many years yet to get enough small amounts of IPv4 addresses to make their content available via IPv4 (even if dual-stacked with v6), then this risks removing much of the industry driver towards IPv6 adoption, and that scenario would be likely to create artificial commerce, black markets and exorbitant effective pricing in v4 addresses, and would favour providers with well-established v4 networks.
So this is another issue I have with the current final /8 policy; I think it's a reasonable idea to have enough addresses for specific purposes for a couple of years while the transition to v6 gets under way properly, but if either it promotes a lengthy availability of IPv4 for new content servers (thus potentially removing IPv6 adoption drivers and increasing IPv4 address value), or it causes an explosion of requests artificially tailored to bypass the intent of the policy (thus potentially causing an inappropriate distribution of addresses anyway, with unnecessary hostmaster workload and impacts upon routing tables, etc.), then I feel it may do more harm than good for the industry.
So the question in this context is what the correct balance in size of space to reserve? The current policy suggests a /8; prop-091 suggests another view.