You're reading your own biases and preconceptions into your source material. The Union of Concerned Scientists post doesn't state that nuclear has lost and renewables have won. All it states is that, as a percentage of net electricity production, renewables are projected to increase, nuclear is largely staying flat, coal is declining, and natural gas has gone through the roof.
Renewables are going to be a huge part of future energy production, but you're deluding yourself if you think that they'll be able to manage 100% in most regions. As renewables displace fossil fuels, they place more and more pressure on storage demands. And just buying PowerWalls and millions of batteries isn't going to cut it without creating other problems elsewhere. The cost analyses that you're referring to do not include storage.
That's where nuclear energy is eventually going to come into play, ensuring that there's a consistent base load available that's not subject to weather conditions. Rolling blackouts are very much an undesirable side effect.