You are missing the problem.

the large majority of racers simply don't care about the Alter Cup qualifier.... its last on the list of events to attend.

In your example.
When given a choice at a popular regatta between a one design class race and a handicap race for the Alter Cup slot the overwhelming majority of sailors will choose the One design Race.

They do not value the Alter Cup Qualifier Slot, a regional interclass championship or the differences in handicap racing. ... So, it's just another local regatta and the strings attached are unacceptable ( don't forget USSA membership)and last on the priority of regattas to attend list.

Basically, they know they will have the most fun racing one design and so WHY should they waste the weekend doing something they don't like?

Either we find a way to make the handicap regatta valuable and interesting to the average racer so that they replace a one design event with the handicap event and show up ... or we dump the qualifiers in areas where we just don't care to play.