The expressions in bold below are incomprehensible to me. Could you please paraphrase or explain them so that they could be easily understood.
Blockquote The literature on the Roosevelt era is immense. Virtually every major participant has written his or her memoirs, scholars have filled library shelves with analytic studies, and the nation’s most prolific writers have addressed the New Deal, the Second World War, and the outsize personalities who dominated American life in the 1930s and ’40s. Biographies of Franklin Roosevelt are only slightly less numerous than those of Washington or Lincoln, and there is little that has not been said, somewhere, about the president. These works are easily accessible to the student of history, yet are seldom consulted by the general public. In recent years, biographies of lesser figures—Truman, MacArthur, Eisenhower, the numerous Kennedys—have shaped popular perceptions of the period. Rummaging through the life of Eleanor Roosevelt has become a cottage industry. As a result, Roosevelt himself has become a mythic figure, looming indistinctly out of the mist of the past.
Could you please explain further about what the word "somewhere" and the phrases "looming indistinctly" and "a cottage industry" actually mean here?
Eleanor Roosevelt, president Franklin Roosevelt's wife, was one of the First Ladies of the US. "Cottage industry", according to investopedia (http://www.investopedia.com/terms/c/cottage-industry.asp), refers to a small-scale industry often operated out of a home, rather than out of a factory. But I don't think it will bring any genuine products out by just rummaging through Eleanor Rooselvelt's life. What does the author intend to tell the readers?