My brother was an all-state cornerback at Maryville in the mid-to-late 1990s just as Maryville was beginning this latest run in football dominance. He was on the team that won the state title in 1998 under Tim Hammontree. He also was one of those to have the lost cause of defending John Henderson while Big John was playing tight end when Maryville lost to Pearl-Cohn at the state championships in 1997. Little brother is 5'8'' at best, so this was a near-impossible task if the quarterback got it anywhere near Henderson.
The key factor was getting the middle schools to run the same system as the Rebels. Once Coach Hammontree got that job done, they developed a factory set-up where the incoming 9th graders had system knowledge. The better players in that group could then be counted on to provide quality depth on the team. It built from there.
The other influences driving Maryville now are population growth and the quality of the Maryville school system.