--Or would such outstanding developments have been non-existent without her ?---
Probably.FDR was much more concerned with keeping Dixie in Democratic hands than he was about extending the New Deal,military service and other civil rights to African -Americans. The beginning of the shift of African-Americans from the Republicans to Democrats began at this time because it was clear blacks finally had an advocate in the White House with Eleanor Roosevelt. Eleanor Roosevelt arranging for Marian Anderson to sing at the Lincoln Memorial in 1939 was another really important symbolic step that demonstrated their was room for blacks with the Democrats . Without her the Democrats probably retain much of their segregationist agenda.No Dixiecrats or Strom Thurmond in 1948 leading to President Dewey? Possible. Would the Republican party take up the mantle of Civil Rights (rather than segregation as it did OTL
) and continue to hold onto the black vote? Questionable.