Because if they actually try they'll be shot dead in the streets by hellfire drones. Texas doesn't win against America. Especially not a gaggle of hicks who can't even spell secede.

A lot of it has to do with Texas having the Gulf of Mexico ports all along the coast. It’s a big reason petrochemical refining is so big in Texas. Another plus for Texas is it’s abundance of land they can either buy or imminent domain. Now don’t get me wrong I’m not a Texas supporter, but it’s just one of those location based decisions I’m sure.

Not to mention if your a business in Texas you usually only get slaps on the wrist when you poison the environment. Worker safety? Mostly dependent on company policy with the main focus just barely making OSHA compliance. If the fine is cheaper than compliance, a lot of companies just pay the fine if it happens.

Because they've been grumbling about that forever and it will never happen unless the US government just up and loses its military.

There will never be the political and populace buy in for something like that to ever end as more than a compound of political extremists getting wiped out by the national guard.

There isn't a snowball's chance in hell they'll be allowed to that's why. In the Texas panhandle is the Pantex plant, which services the military's nuclear warheads. You saw what Uncle Sam did to the people who touched his boats, now try touching his nukes.