"are we going to see most of these folks put the money into another J/30"

Short term - probably not. Right now New Orleans is like Pompeii - only with water instead of ashes.
All facilities associated with boating are destroyed. Marinas and slips - out, fuel docks and repair yards - out, retail parts stores (West Marine, etc) - gone, yacht clubs - out. All of the things needed to support boating are gone.
The J-30 owners who lost boats in Katrina/Rita are in the midst of non-boating life cycles - Blue J, Halfaglass, and Zephyr are fathers of infants. They were very active sailors BK. In the family battle between boat and infant for time and money, boats usually lose. Maverik was seldom used BK and I'm sure it won't be replaced. The insurance settlement from my boat, Gritz will go into the bigger-house down-payment-kitty.
On the other hand, each of the owners already has parts, sails, and knowledge of J/30's. And a J/30 is a great boat for Lake Pontchartrain.
So short term, I see no significant boat replacement on Lake Pontchartrain for any model, and probably more local boats being sold as people try to rebuild their homes and businesses.
Slowly facilities will come back. Once boating facilities return, and people's lives and careers stabilize, then boating will slowly return.

MHO
George