Sauron and Saruman?

[the phantom]

Sauron would have been enslaved not annihilated, and the Dark Tower would not have been destroyed but occupied.

Yes, that's been my main point all along. If the ring wasn't destroyed then Sauron and his works would have endured, his downfall not complete.

And definitely, like I said earlier, Gandalf, Aragorn, or some other powerful person could have used the ring's power and overthrown Sauron and his empire, but since the ring isn't gone niether is Sauron.

Being overthrown by a new ring lord would be a huge set back for him, who knows how long, but as long as the ring exists it's only a matter of time before he wins.