Why does everyone think Texas is all desert?

When I lived Back East everyone was certain Texas was full of cowboys living on ranches. They envisioned it being the Wild West overwhelmed with sand, cacti, and tumble. First off, tumbleweed is native to Russia, and it was imported here. Second, cows cannot graze in the desert where there isn't enough gr. Why don't people understand that the vast majority of the landscape here is prairie? Hardly anyone lives in the desert out in West Texas. In fact, that area has lost population. Further, many are convinced that we live agrarian lifestyles in rural areas. More than 80 percent of our population resides in urban areas east of I-35 (which traverses the Balcones Escarpment that separates the Gulf Coastal Plain from the Edwards Plateau.) A large chunk of East Texas is swamp land and dense forest. Where I grew up is predominately gl, steel, and concrete. Houston now has over 5 million people. Plus, the natural vegetation there is dominated by live oaks, cypress, and pine trees. Why don't people ever have that image about Texas?