This story is flat out wrong. we are already connected to the other interconnects, this is just a 4th one (albeit a big one). ERCOT is still managing as normal. Also the connection can go both ways or be turned off. We actually supply a lot of power to the other grids.
Texas actually sells a lot of the wind power to the other interconnects already through the existing connections. You can watch it on the ERCOT dashboard.