It is expensive and complicated to build new (especially large) buildings in central city districts, compared with green field sites on the periphery of cities.
I assume what Youngalum is talking about is the likes of high profile corporate users such as Toyota selecting a suburban campus on a never developed piece of property, in a large, homogenous suburb like Plano.
Some new development will occur out in places such as suburban office parks. And some will occur in central city locations such as Downtown Fort Worth. The companies' decisions likely have a lot to do with their idea of their target employees, and what sort of environment they predict will appeal most (within their budget constraints) to that future, undefined employee and their existing staff. So it comes down to taste. Does the leadership think its better to be in a new office park where everyone drives to a chain fast food place for lunch each day, or in a dense, walkable downtown environment, where they have to maybe deal with some inconvenience or expense of parking in a garage? They probably have different types of target employees, and often existing employees to consider.
I obviously have a preference for downtown, walkable places and would go out of my way to choose that location.
Thankfully, thousands of people and companies choose the same way and have demonstrated that they love Fort Worth's central core and are willing to pay a bit of a premium to be in Downtown Fort Worth and, in the case of Jetta, make a bold, ambitious statement of designing a new, modern building right in the middle of the walkable urban core of Fort Worth.
Its probably cheaper for most companies with highly sought after talent to pay more for really great office space rather than lose talent to competitors who offer better work environments.