Who else could have aided Gondor?

[Kuruharan]

Originally Posted by Rhod the Red

The dwarves of the Blue Mountains.

But that'd mean them giving up mining there, the Elves of the Grey Havens lending/staffing the craft there to take them to Gondor.

Highly impractical, I fear, given the distances involved. There also were not many dwarves in the Blue Mountains so they would not have been able to provide much aid.

Also, dwarves did not fancy the sea very much and would probably not have wanted to sail there.

And then there is what Inziladun said...