Tedd, I believe those styles are only for screw in (carbon / aluminum) which can be gotten in 32" lengths (at least the carbons).
Even those with slightly less draw can use a longer wood arrow. I draw around 30.5, and although field points work great, it creates problems with broadheads when using a 31" woodie shaft.
I am guessing that the reason for the current length is that the standard used to be 28" draw, period and arrows were made to accommodate that, and the equipment used to create those shafts made them just long enough for that.
ChuckC