Your logic may be true for a power conference team, but not a conference like the MAC. It's really easy to make the NCAA Tournament in a power conference team as long as win 20+ games which includes a November and December of 300+RPI teams, a few of those on the road, and avoid bad losses, especially at home. While the RPI used to be a solid number for judging the strength of teams, the power conferences have more or less vanquished it's usefulness by their unwillingness to play outside of their own arena against a midmajor.