Greg,
I don't think people are claiming that Texas is a wasteland. The part that surprises me is how few courses in such a big state are truly "great" when viewed on a national scale. To me the term is reserved for the very best, and I don't think that courses in the 2nd 100 on GolfWeek's Modern Listing necessarily qualify.
The greatness issue really isn't confined to Texas. If you look at the southernmost states in the United States, how many of them have truly great courses? South Carolina and Florida have a few each, but given the sheer quantity of courses in those states they should! Georgia has a few. Alabama, Mississippi, and Louisiana might not have any depending on the criteria--maybe Shoal Creek. Texas we've covered! New Mexico probably doesn't have any, although I'm a homer and like Paa-Ko and Black Mesa a lot. Arizona might not have any either. I like Forest Highlands and We-Ko-Pa Saguaro and others like Desert Forest, but none of them are fixtures on all the top 100 lists. California's best are on the west coast.
It really is amazing (perhaps not surprising, though) how many of the best courses are on the two coasts. I used to try to deny that, but now that I've played quite a few of them it has become hard to argue.