Why hasn't Terrell Davis made it into pro football's Hall of Fame?

As a Bronco fan I enjoyed watching TD. He had three spectacular rushing seasons(1,538 yards in 1996, 1,750 yards in 1997, 2.008 yards in 1998), and besides John Elway, he was the most important player on the Broncos' two Super Bowl championship teams. Unfortunately, TD suffered numerous injuries(to his knee, ankle and foot) and was forced into retirement after seven seasons. If he'd stayed healthy, I think he would have had unbreakable rushing records. TD was a Hall of Fame finalist this year. I hope he makes it in next year.