"Dr. Doom" economist Nouriel Roubini is now more optimistic about the US economy.  
He sees AI and fusion energy driving a boom, with GDP growth possibly hitting 4% by 2030.  
The S&P 500 could keep rising at a steady pace through 2025.  
AI’s impact is growing fast, fusion is nearing reality, and markets adapt better to Trump policies.  
While risks like geopolitics and debt remain, he calls them "manageable."  
Roubini says he’s always been a realist—not just a pessimist.  
The "Dr. Doom" labe