I don't think anybody except lobbyists argue for that. In most projections i saw from pro-nuclear anti-carbon think tank (such as the one i was memebr of during Covid), the nuclear part in the energy mix vary from 30 to 50% (Depending on what the nuclear would be present for: i think in the 50% model, 60% of nuclear should be controllable plants, vs 100% for the 30% model).