John Tolkien was telling a story, and playing an RPG is not the same as telling a story*. It is a poor GM who relies on contrived coincidence to steer the game in a certain direction. He could get away with divine providence in a novel, but a game that relied upon the same would be distasteful, and discerning players would shout him down as a no-good dirty railroader (or just roll their eyes heavily, depending on how polite they wanted to be).
*Unless you're playing one of those new-age hippie-RPGs that is based on story-telling rather than role-playing.
It seems to go without saying that my players lack discernment and that I'm a poor GM. So I'll leave that to speak for itself.
As far as railroading is concerned - my game is not a railroad. I posted a link upthread to a report of my session yesterday. Nothing that happened in that session - the players' decisions on what actions to take, one of the PCs learning the Raven Queen's true name, the existence in the mausoleum of a Chariot of Sustarre, the PCs getting to borrow that chariot, etc - was pre-planned.
Consider the chariot. The player's PC is in a mausoleum of a mighty sorcerer queen. He asks if there are grave goods - I answer yes, and decide (on my previously underpopulated map) where they are and explain that to him. (His character is looking around the appropriate part of the mausoleum). He then asks "Is there a magical flying chariot?" I answer yes, there is. We then resolve the PC's request to the tomb guardians to be allowed to borrow it.
I suppose someone somewhere regards that as a railroad and as a removal of the players' agency. I'll await the explanation.
Fate and destiny contradict the notion of free will, within the game world
<snip>
Where a game is supposed to be a series of meaningful decisions, those decisions are no longer meaningful if the DM is (for example) actively framing the party into a scene.
Because telling a player "You see your mother in the goblin cell across from your own" precludes meaningful decision? Because telling a player "With you new-found divine sense, you sense a terrible abomination waking from its slumber deep in the earth and rising to the surface" precludes meaningful decision? Again, I await the explanation.
(Perhaps you're not familiar with the difference between pre-scripted "scenes" ie an Adventure Path, or the Alexandrian's "Node-based design" variant, and a "scene framed" game in the way that phrase is normally used.)
As for fate and destiny: these are preeminent themes of fantasy film and literature. And you can have destiny as a very significant feature of the game without railroading: what the destiny actually is emerges via play.
Here's a simple example.
First, you run a scenario in which the PCs travel back in time. While they're back in time, they find an apprentice wizard trapped in a mirror. They free her and befriend her, but then leave her behind when they return to the present.
Some time later, the PCs are going to visit a baron and you (as GM) are wondering what the action might be. So you come up with the idea that the baron is descended from the apprentice, and that his niece is her doppelganger. And when the PCs turn up at the castle to dine you narrate the wall of family portraits, where they can see a portrait that resembles the apprentice, but aged; and another portrait that surely is of the apprentice, but is clearly painted more recently than the first-mentioned one.
Now the players have a sense that, somehow, their fates are interwoven with those of the apprentice and the niece; though they don't yet know how. (And nor does the GM.)
No railroading. And meaningful choices - for instance,
if it turns out that the niece is missing (say, that gets narrated by the GM as part of the playing out of the dinner with the baron), then the players (in person, and in character) feel that her fate
matters to them in a way that it otherwise probably wouldn't, because she is somehow connected to the apprentice they rescued from the mirror. And so the choices that they make - whether to rescue her, what to do if it turns out that she is an evil necromancer, etc - matter more than they otherwise would.