I agree with the first part, but not the second part.
From 1998-99 to 2005-06 the BCS was just the Rose, Sugar, Fiesta and Orange with one of those serving as a championship game on a rotating basis for a total of 8 teams that could participate. KF made one of these and lost in the Orange Bowl in 2003.
From 2006-07 to 2013-14 the BCS was just the Rose, Sugar, Fiesta and Orange with the national championship game playing a week later at one of the four bowls on a rotating basis for a total of 10 teams that could participate. KF made one of these and won the 2010 Orange Bowl.
Now we have the NY6 with the aforementioned bowl games while adding the Peach and Cotton Bowls for a total of 12 teams. KF made one of these and lost and MC made one and won.
It was much harder to make a BCS bowl from 1998-99 to 2005-06 than it is to make a NY6 Bowl now. Making a BCS bowl from 2006-07 to 2013-14 is harder than making a NY6 bowl now.
I don't think ISU would have made a BCS bowl under the 1998-99-2005-06 criteria, but probably would have under the 2006-07 to 2013-14 criteria.