What the article shows is that:
* Texas's power providers were not adequately winterized.
* The regulatory standards of the larger grids would not have caused them to be so, even if they were subject to them.
* Nearby states suffered outages due to the cold as well, even though they're connected to the larger grids.
* It is unlikely that Texas could have made up the loss in generation power -- estimated to be as much as ~45GW at times -- by drawing on the other states. States near to Texas don't generate nearly as much power and power is not like sunshine, diffusing evenly over the grid from every point.