DL -- like all carriers -- uses sophisticated revenue and inventory management software which predicts the demand for seats at various prices. Right now, DL is predicting that it will sell those seats at $700+. If it can't, DL can open up some seats in a lower fare bucket.

But, given capacity cuts and an improved economy, as a complete generalization, I would expect more fare buckets to go to 0, not the other way around. From the traveler's perspective, it is more likely that prices will go up from $700 rather than down.

By way of example, if you needed a close-in ticket LAX-ALB later this week, it's current price is $1,100 - $1,300.

Me? If I knew I had to travel, I would book the $700 and consider it done.