Back in the early 1990s, Texas Instruments was looking for a district to bring its patent litigation. The federal district courts in Dallas and Austin were clogged with criminal cases. East Texas was relatively open for civil suits to proceed quickly: https://www.texasmonthly.com/politics/patently-unfair/

The district is also not as random as people make it out to be. It’s a few hours east of Dallas, and includes some of the rich suburb/satellite cities like Plano. It’s got a significant oil and chemical industry.