I looked at the teams that have won or made the title game since 1986. You can interpret the numbers as either supporting or refuting parity.
In favor of parity:
29 teams have made it to the championship game. Considering that there are 52 teams in 4A now, that would be 55%. However, 16 of the 29 teams are not now in 4A (5 in 2A, 7 in 3A, 4 in 5A). I haven't looked at other groups, but I'd guess that 40%-50% of teams in the state have made it at least once since 1986.
16 teams have won the championship, so a majority of wins are by teams with one title (10 teams).
Against parity:
4 teams (Salem, Amherst, Briar Woods, Spotsylvania) have combined to capture 16 out of 30 titles.
Salem and Amherst have combined for 15 championship game appearances, which is half of the "western" appearances if you define west as Regions III, IV, 4A North, and 4A West.
14 teams have appeared in one championship game only and have a combined record of 3-11, so 27 titles have been won by teams making more than one appearance. Only two teams making more than one appearance failed to win a title (Harrisonburg, Sherando).
In favor of parity:
29 teams have made it to the championship game. Considering that there are 52 teams in 4A now, that would be 55%. However, 16 of the 29 teams are not now in 4A (5 in 2A, 7 in 3A, 4 in 5A). I haven't looked at other groups, but I'd guess that 40%-50% of teams in the state have made it at least once since 1986.
16 teams have won the championship, so a majority of wins are by teams with one title (10 teams).
Against parity:
4 teams (Salem, Amherst, Briar Woods, Spotsylvania) have combined to capture 16 out of 30 titles.
Salem and Amherst have combined for 15 championship game appearances, which is half of the "western" appearances if you define west as Regions III, IV, 4A North, and 4A West.
14 teams have appeared in one championship game only and have a combined record of 3-11, so 27 titles have been won by teams making more than one appearance. Only two teams making more than one appearance failed to win a title (Harrisonburg, Sherando).