By age 25, Edward S. Lampert was already a Wall Street wunderkind, celebrated for his intellect, ambition and prodigious work ethic. The famed investor Richard Rainwater, the billionaire Hollywood mogul David Geffen, and Michael Dell and Thomas J. Tisch were among the prominent backers who gave him more than $200 million in startup capital. At 28, he was the subject of a front-page profile in The Wall Street Journal headlined “The Climber.” His hedge fund’s 29 percent annualized return landed him on the cover of Businessweek in 2004. Forbes pegged his net worth at $3.5 billion that year.