The answers aren't that difficult but the motivation is hard. It may be a cliche but neccessity really is the mother of invention. For instance, the day that we accurately calculate the exhaustion of fossil fuels in one persons lifetime is the day that real energy innovation will begin.

1. Profit - When someone figures out how to make tons of money by moving tons of payload into space, we will be on our way. Private enterprise will find a way. This will take a while but some of the ground work is being done. As long as there is more money to be made on Earth, space is going to be on the back burner.

2. Political imperative - the fastest way to jump start the space program would be another space race like the Apollo progarm. If China sets their sights on Mars we will mobilize and get it done. The money spent in Iraq would have funded a permanent base on the moon and Mars. The government funded research would also make number one happen quicker.

Of course, we would find something else to spend all that money on without some rival nation providing the urgency. Assuming we are still a solvent nation we will never let another country stake a claim in space before us. Unfortunately, under our system the urgency will never be there until some planned economy like China forces our hand.

(the bastards don't care that I am running out of waiting time)