[Inziladun]

I think that might oversimplify Gollum's problem.

I don't think he was "addicted" to the Ring: It, being filled with the will and spirit of its maker, had attained almost complete possession over Gollum. From his first sight of the Ring, he had wanted to possess it, but that desire had utterly backfired.
It seems to me Tolkien's point is that when we think we possess something badly enough, we are the ones possessed, in thralldom. Aragorn says as much to Pippin about the latter's casting away of his treasured Lórien brooch: 'He who cannot cast away a treasure at need is in fetters'.

Also, I wouldn't put all the blame for Gollum's ultimate treachery on Sam. True, his misunderstanding of Gollum's behaviour on the Stairs of Cirith Ungol was apparently the last straw. But, as the Slinker/Stinker debate overheard by Sam long before indicates, Gollum had thoughts of turning on Frodo apart from Sam's mistrust of him. And the lust for the Ring was too much for the kindness of Frodo to overcome.