I seem to have struck a nerve. Those are not large cities. These are the largest cities by population for metro area in each of those states that I was able to find with some quick googling.
Little Rock - 738,344
New Orleans Metro - 1,271,320
Baton Rouge Metro - 854,884
Jackson Mississippi - 597,727
All together that's about half of what's in the DFW area.
DFW - 7,637,387
If you were to hold a single motorcycle show in a location where all of those cities could participate you are likely to get less than half the attendance of DFW. A centrally located show would have about the same driving time as coming from Houston to Dallas so we can add another 7 million to the above number by population. We do have folks ride up from Houston once IMS figured out to not have a show in both cities.
I'm not trying to belittle anything, just looking at the numbers. If Honda, Suzuki and KTM decide to skip a show in a city of over 7 and a half million people because it's not as big as say, the 18 million in Los Angeles, then I ask again, what makes you think IMS could convince them to show up at a city of 1.2 million? They even dropped Cleveland with it's 2 million people off the schedule.
Every year the attendance drops, and the manufacturers drop, which causes the attendance to drop. If they can't figure out how to fix this, cities will keep dropping off the list and we won't have a show at all, so moving to smaller markets is a slim possibility at this point.