Why exactly was the Office of Strategic Services succeeded by the Central Intelligence Agency?

Before World War II, the United States had never had a
formal intelligence agency.  The task of gathering and processing intelligence had been
split between many different entites.  At the end of the war, President Truman dissolved
the OSS, thinking that the US could go back to the way things had
been.

However, with the Cold War coming on, this was
clearly not feasible.  It was clear that the US would need one agency to be in charge of
all intelligence so that the process of gathering and analyzing the intelligence could
be made as efficient as possible.  It was due to this that the CIA was created.  It was
given powers that the OSS had never had.  It became the major agency that was
responsible for all intelligence work.

The CIA succeeded
the OSS, then, because there was a need for a centralized intelligence system and
because the OSS had not had the powers needed to play such a
role.