Starlink is an access technology. The Tier 1 backbone providers of the Internet are still terrestrial which means terrestrial fiber and submarine cables. Starlink still has to buy transit from the people with fiber. I think Starlink purchases transit from GTT, Lumen, Zayo and buncg of others. A fiber cut could still impact Starlink. Think of what happens when your ISP goes down but the Wifi on your routers is still up. It's somewhat similar.