"Live Oak" is generally the same thing as calling something "Ironwood"; neither "specie" exists singularly.
There are several live oaks. They are sort of the equivelant of "evergreen" softwoods. Live oaks stay green year-round or almost year-round. There are also many "Ironwoods". For example, the Southern Live Oak is a specific specie of the general group of live oaks. It has the highest density of any North American hardwood regardless of much disinformation otherwise. Could some regions call "Live oak" an "Ironwood"? Of course.
What you're seeing is the harvest of the (SYP) southern pines going down the highways because they are the most profitable commercial tree in the southern states. SYP is the best commercial framing timber bar none.
That doesn't mean hardwoods, including oaks and other genus' aren't being harvested though. You just aren't seeing the pulp logs, the tie logs, and the hardwood grade logs being hauled also because where you live they are simply not as profitable. SYP because is the backbone of many industries. Not only in this hemisphere but the whole planet.
You live in a region which has one of the most cost-efficient growing/harvesting environments for a commodity that has a worldwide demand. SYP is in demand even when housing starts are down because it's a commodity that is the best option for a wide array of markets.
Sunshine, moisture, and soil content play a very large role. The lack of unions doesn't hurt either but I digress.