Because they don’t want to drive 2 hours to work one way. And, because that’s the asking price. So, if you want to live near the city, you’re going to pay.
There’s still cheap land in Texas. Way out in west Texas in the middle of nowhere. But people like city water and sewage treatment. Out in the country you have to drill a well and install a septic system. That can add up to $20,000 to the cost.
The lesson for Houston from places like Atlanta is that, eventually, the jobs, water lines, and sewer systems migrate to the exurbs where many people want to live. Maybe that will eventually happen in Houston.