Plaintiff didn't get the votes she needed to have the appellate court's decision reviewed. Chief Justice Jefferson and Justice Lehrmann noted their dissent to the denial. The order was "petition denied" and not "petition refused" so arguably Bostic is just the law of the Dallas Court of Appeals, 5th District and not the law of Texas.
What's likely to follow?
Any defendant whose act or omission cannot be shown to have been sufficient to produce (i.e. capable of generating the effect without the need for any other exposure or action) the harm of which plaintiff complains will move for summary judgment. Particularly in those cases in which the independent actions of multiple defendants produced an indivisible harm and plaintiff cannot show that the act of each alone had the potential to produce her injury.
Odds are the effect of this ruling will first be explored in Texas' asbestos MDL. We'll let you know how it goes.