White Sox attendance issues started in the mid 1960's when social unrest created the myth that Comiskey Park was a "dangerous" place because of its location. Nothing the Sox could do about that but they have shot themselves in the foot over the years with decisions like leaving WGN-TV, creating SportsVision and saying "We are Chicago's American League team..." instead of taking on the Cubs full-on.
From 1951-1967 the Sox outdrew the Cubs in 16 of those 17 years sometimes by a wide margin.
Part of the issue is the Sox have not been able to consistently put a winning competitive streak like that together since then.
Often they come out of the blue (like in 2005) and have an excellent season but they...can't...keep...it...going. I don't mean winning World Series after World series but how about making the playoffs say four times in six years or five times in seven? Sox have never done that.
They'll have a nice stretch (1981-1983, 1990-1994, 2000-2006...) and then it's back to mediocrity.
To say nothing even about all the controversies...Sox are moving...stadium controversy, JR and 1994 labor impasse, White Flag Trade, cancelling Sox fest, bizarre new ticket policy among others.
That's no way to build a fan base in my opinion.