I did not take from that article that the decision to put 130 where it is was driven by land speculators. That actually seemed like the least discussed issue in the location.
It sounded to me that the other local governments that would be affected by the alignment, rightfully, chose what was best for their communities, and that there was far more emphasis and discussion based on how many existing residents would be displaced and surrounding existing residents would be affected by the route. Throw in a little bit of "Smart Growth" restrictions and a few environmental concerns and I think that is how the route was chosen.
A City of Austin planner was quoted in the article saying that the surrounding communities (Lockhart, RR, Georgetown) should be annexing the areas.
So it still sounds like it wasn't an Austin decision of where 130 got dropped.