We have seen throughout the Silmarillion and other Middle Earth related histories that the forces of "Good" (Elves, Edain, Naugrim etc) constantly sit and wait for their enemy to get stronger before acting.
Whilst this is understandable early in the mythos (the Valar did not want to make war on Melkor until the location of the children of Illúvatar was known), it was in my opinion inexcusable later in the mythos.
The Noldor were too content with their realms in Beleriand and Hithlum to challenge Melkor during the siege until they were destroyed because he was developing his forces all the time.
The elves of Gondolin refused to proactively fight until they were found and destroyed.
The white council refused to attack Dol Guldur, preferring to watch and wait until Sauron was too powerful (that may have been due to Saruman's own plans).
Gandalf prefered to watch Frodo and the ring for 17 years despite being suspicious. Wouldn't it have been safer to watch Frodo in Rivendell or Lothlórien for those years, with the possiblilty of his returning to the Shire should Gandalf be incorrect.
I am sure there are other examples but these are off the top of my head.
I know there are reasons given for each (eg Sarumans influence for point 3) but given the experience of (particularly) Elrond and Galadriel and other elven/Istari lords wouldn't it have been obvious to deal with a threat now before it possibly becomes unmanageable?
(Out of universe these all make uber wicked stories but in universe explanations please).