Deadly, long track wedge tornadoes - how does the gulf coast seem to avoid them?

Southern Louisiana gets nailed with powerful hurricanes fairly regularly, but the powerful "dixie alley" wedge tornadoes that are very destructive in places like Jackson, Memphis, Oklahoma City, and Birmingham seem to rarely be a problem south of McComb. Cities like Biloxi, Mobile, Baton Rouge, and New Orleans are far less likely to get them than areas to their north.

Even looking through the tornado track history of Louisiana, the farthest south I was able to find a record of a longer track F-3 or higher tornado was in Pointe Coupee/West Feliciana in the mid 1960s.

When I say "wedge tornado", I don't mean the smaller ones that have hit the Baton Rouge area fairly recently. I mean the quarter mile-mile wide cyclones that level entire towns:



Tornado frequency map:



Hopefully the OT weather and climate experts can weigh in. Is this related to typography or some kind of weather pattern driven by the moisture on the gulf coast?

Would hurricane straps, wind rated windows, and sheer walls (required in some parts of Louisiana and Florida) be effective against powerful tornadoes? Are reinforced storm shelters even a worthwhile investment for a new home along the I-10 corridor in TX/LA/MS/AL?