Like OBK has posted...take a look at some of those schools that played 11-man then switched to six-man...Strawn and Cherokee for example (in the 1960s)...then look at what year they made that switch...then look at what the town was like for 5 years leading up to the switch...then look at how those towns hacve been after the switch...I am about to say something that may shock some and I do not remember anyone else ever saying this as a hypothesis...but here it goes...maybe perhaps the rule is a town is in decline and after the move to six-man...for what ever reason...the town levels out and holds realitizly stable over time.
So just maybe a move to six-man helps a town realize they are in decline (for what ever reason) and the move to six-man acts as a catalyst to help those communities make changes within the community that helps stabilize them.
Now some towns it doesn't work for perhaps due to location, and some towns for what ever reason are just in decline and on the verg of closing the school, but like I said I think these are more of the exception instead of the rule.
OBK-
Aquilla played 11-man four years 1980, 81, 82, 83
1984 Aquilla moved back to six-man
(ps: their first district championship was in 1970)