Short version....
Bud Adams threatened to move the Oilers to Jacksonville unless we ripped out the scoreboard (affectionately known as the pinball machine) to add 10,000 more seats. A few years later, Bud "the bad rug" wanted a brand new stadium and the Mayor (Lanier) balked - claiming that the tax payers were still paying for the renovations to the Dome. The p****ing match lasted for a while and in the meantime - Nashville was putting together a sweetheart deal for Bud... He took the deal and moved the Oilers to Memphis where they played for a season or two waiting on the new stadium to be ready in Nashville.... When they moved from Memphis to the new digs in Nashvilled they also made the transformation from the Oilers to the Titans.
Hypothetically the same thing could happen to the Texans, but then again, that could technically happen to any team in the NFL except the Green Bay Packers. The NFL is a business and Owners of businesses can do what they want with them, providing that they do not break any contracts or leases, etc. - for the sake of the move.