It bears clarifying that I am not saying the Fast movies are as important or well done as Tolkien’s writing, but Diesel is not wrong to say they are somewhat similar. For one, both the saga and Tolkien’s writing (and the movie adaptations too) are earnest to the core. No matter how dire, or ludicrous the story gets, they retain the same huge heart and sincerity. After all, what is “The Two Towers” without Sam’s speech? What is the battle of Barad-dûr without Aragorn’s gentle and soft-spoken “For Frodo”?
Say what you will about how dumb the Fast movies are, or how going to space is just ridiculous, but there is no denying that those movies are all about family, at least now. It is that sentiment that has allowed them to sell the craziest parts of the story and ground them in character and in emotion.
Then there’s the other part, the mythology of it all. As Diesel said, continuing mythologies and expanding them is not easy. The Fast franchise is constantly retconning itself, twisting, recontextualizing, and adding to its mythology in a way few franchises in Hollywood do. In a way, isn’t the story of Dom Toretto, with all its twists and turns, characters returning from the dead, secret siblings, and more just as larger-than-life and mythological like the tales of Fëanor and Elendil, or Frodo and Aragorn?
It makes sense for Diesel to see the similarities, and even encourage them, with the Fast Saga becoming more and more complex and mythological. Diesel is famously a huge “Dungeons & Dragons” nerd, to the point where he literally got a movie made about his D&D character, “The Last Witch Hunter” — the coolest act of fan fiction you can do.