The DSA business model, as tested in the public inquiry in 2003, was to poach the vast majority of their passengers from Manchester, Leeds-Bradford and Humberside. They grew in the first two years and it's been downhill ever since. It was always a shaky business model. It started to fail before the downturn.
The passenger numbers increased for the first 3 years, and started to dip in July 2008, which is when the economy started to go pear shaped.