What if Gollum had lived?

[Tuor in Gondolin]

And yet but for Sam's clumsiness and protectiveness towards Frodo Gollum might have repented.

Letters #96

...For myself, I was prob. most moved by Sam's disquisition on the seamless web of story,
and by the scene when Frodo goes to sleep on his breast, and the tragedy of Gollum who at that moment
came within a hair of repentence-but for one rough word from Sam.

[Moonraker]

Originally Posted by Tuor in Gondolin

And yet but for Sam's clumsiness and protectiveness towards Frodo Gollum might have repented.

Letters #96

Repented for how long? Surely the realisation that Frodo was on a quest to destroy the Ring would have stirred up the evil in Gollum again?

[Inziladun]

Originally Posted by Moonraker

Repented for how long? Surely the realisation that Frodo was on a quest to destroy the Ring would have stirred up the evil in Gollum again?

Tolkien wrote, I think in that same letter cited by Tuor, that ultimately the Ring would have been too strong for Gollum, and the repentance would not have been permanent.

[Moonraker]

Would Gollum, being a previous Ring Bearer, be commanded to sail with the Company over the sea? Provided the old rascal could contain himself, tied up but treated with care?

[Inziladun]

Originally Posted by Moonraker

Would Gollum, being a previous Ring Bearer, be commanded to sail with the Company over the sea? Provided the old rascal could contain himself, tied up but treated with care?

No. Frodo and Bilbo were not "commanded" themselves. It was a privilege granted because of their particular roles as Ring-bearers, and in recognition of each's love for the Elves. Gollum would not have gone, even if given the opportunity. His inability to touch the rope made in Lórien or eat lembas is an indication that the West wasn't for him.