First of all, even greater? I don't know. The guy is a Hall of Fame running back. Super Bowl champion, Super Bowl MVP, league MVP, Offensive Player of the Year, Offensive Rookie of the Year, Comeback Player of the Year, 6x Pro Bowler. That's a pretty impressive resume he accomplished.
Secondly, Marcus Allen is NOT the only player with 10,000 rushing and 5,000 receiving. My pick for the best running back ever has more yards on the ground than Allen, more yards through the air than Allen, more touchdowns than Allen, more Pro Bowls than Allen, more All-Pro's than Allen, AND holds the record for most times named Offensive Player of the Year.
Also, Tiki Barber has eclipsed both 10,000 rushing and 5,000 receiving.