An unmanaged oil collapse will likely lead to starvation, disease, political, and technological chaos. Recovery from this will be difficult, or impossible.
If we can get our leadership to face the reality of peak oil, we might be able to live in a better world someday. I don't think pure market forces have the heart to make this happen. By the time it is profitable, it may be too late.
A managed, positive outcome may occur if technology is used to cushion the effects of oil depletion, and allow time for a natural age based die off to reduce the population gracefully. If we can make extreme gas & oil conservation and population reduction critical priorities, we might be able to use our remaining gas and oil resources to develop the means of sustaining a small population. The result would hopefully be a small, healthy, and technologically advanced human population living on a much healthier Earth. This is better than a return to the stone age.
This is certainly a more worthwhile make-work and spending project than a trip to Mars!