I feel deeply that Reylo is going to be endgame for Star Wars and this is because that they (as a couple) are different than the other Star Wars couples in just the one way...
I’m only using Han/Leia and Anakin/Padme as examples here because that’s the movies and the medium that we are dealing with when it comes to Reylo. IMO one of the biggest similarities between these three relationships is the equality (or lack thereof) between the partners.
Anakin was a slave and Padme was a queen who became a Senator.
Anakin was strong with the force Padme didn’t use the force (That I know of? There might be some piece of small something in canon that shows her as being the slightest bit force sensitive. Whether she was or not - I’m still sticking to what we can see in the movies.)
Han was a “scoundrel” and Leia was a princess who became a general.
Han is not force sensitive and Leia is incredibly force sensitive.
Rey is a scavenger and Ben has that Skywalker blood and eventually becomes the leader of the Knights of Ren. He’s got the whole ~dark prince~ thing going on.
Now... this is where Reylo sets itself apart. Rey and Ben are equals with the force. Snoke refers to Ben’s equal in the light growing as he does and immediately changes his mind about that being Luke when they discover Reys powers.
This is a BIG difference... these shared force powers set them apart because even though they come from vastly different backgrounds/family/etc., they are equals. No matter what their power statuses were before the beginning of The Force Awakens and no matter what they remain through the rest of the trilogy, Rey and Ben are equals in the force and that speaks volumes about how they would last as a couple.
These last 2 trilogies have sort of shown us that love doesn’t really work in Star Wars, but that’s because up until the end of this trilogy the galaxy hasn’t been balanced (That is me just hoping/assuming that the galaxy will be in a better balance by the end of this sequel trilogy).
The bottom line, I think, is that Ben and Rey are the first primary couple presented in the Star Wars films that are placed, in some way, on equal footing and that’s going to GREATLY benefit them in the long run. I don’t know how they’re going to get together and I don’t know what the consequences of them together will be (where they stand as far as light/dark/grey) - but I do REALLY think that we will have Rey and Ben by each other’s side in a romantic way at the end of the trilogy.