Before that six-year statute of limitations was in place, the Government of Canada was basically using whatever statute of limitations was in place in the student's province or territory of residence. Those statutes varied across the country. Some were as low as a two-year statute of limitations. The idea in 2003 was to establish a consistent statute across the country for Canada student loans, regardless of where the student resided. The six years was chosen as the reasonable upper limit of what was in place in the provinces at the time.
On November 29th, 2011. See this statement in context.