Because that's not the overall point of the story. It's backstory. We got enough of the backstory as is in TLJ.
LOL. Thats a terrible miscalculation from LucasFilms storygroup. Shows you how out-of-touch (or mishandled by higher-ups) they are. There is a huge amount of historical baggage in using Luke Skywalker (or any character-driven media in general) in any new Star Wars movie even if its just for a supporting role. As i said earlier, you wanna alter main character traits of the lead protagonist from the OT you better do due diligence with the buildup on his backstory changes. Something that TLJ writers and director did not do . . . . and thats why a significant number of Star Wars fans hated TLJ for what it did to Luke's character.
Seeing a literal vision of the future where Kylo is directly responsible for the death and destruction of everything Luke loved. That vision came true, as it always does. It's not an example of mere temptation, Luke was seeing the future. He was feeling, the future.
In terms of 'shit just got real' severity scale, force visions about some terrible
future involving your nephew is still pretty low compared to your Sith Lord father trying to kill you for the Emperor and your family and friends in the Rebellion getting massacred at the
present time.
Luke handled stress and situations getting pear-shaped pretty well(ie. Second Death Star is actually fully operational, surprise!) by the time RotJ credits rolled in. No reason for him to be written as some impulsive, weak-willed newb toward negative force visions involving Ben Solo in TLJ without proper build-up and backstory changes. Force visions are too weak a reason for a SW audience to believe that Luke would go straight contemplating a lethal solution in dealing with his nephew. There should be more TLJ build-up scenes showing the gradual erosion of the uncle and nephew relationship to sell that final breach in Ben Solo's bedroom.
Luke didn't bust into his room thinking he needs to kill him. Why do you keep misdescribing the scene?
Doesnt matter if TLJ Luke kicked the door down or just went through because its open . . . . he is still in his nephew's room with an ignited lightsaber. Anyone in Kylo's position is going to act and think of self-preservation. And Luke was conveniently written by the TLJ writers to be a deaf-mute Jedi Master unable to explanation the situation to his nephew to try and redeem him.
Luke had no idea that any of this was even happening and spent years suicidally depressed. That's the whole point. He realizes that he made an incredibly severe mistake and sacrificed himself for it. You are still thinking about the idea of Luke instead of what Luke is like as a person. "Oh he's my fan favorite jedi master, HE SHOULD ROBOTICALLY RESPOND LIKE THIS." It's like the entire commentary about expectations and how Luke was dehumanized and the weight of all that finally crashing down on him when he experiences his first major failure flew over your head.
TLJ writers are free to 'humanize' - whatever that means, Luke is pretty down-to-Earth dude even when he was a Jedi Master - and explore the concept of 'failure' with Luke Skywalker . . . . its just that the 'failure' plot and story they come-up with in TLJ was STUPID and has a FLIMSY backstory foundation (ie. dark thoughts and visions, must kill nephew, noooo, *clunk on the head*, mah students NOOOoooOOOO, SHAME!,
Sorry Leia your on your own, even though your husband left you, even though i still havent redeemed your genocidal son , imma gonna leave you and mop around some far-off planet!). His 'sacrifice' at the end of TLJ feels weak because of this.
TLJ Luke was inconsistent character-wise with his previous end-of-RotJ depiction. His backstory needed more TLJ scenes to flesh-out whatever character changes happened in particular to his relation ship with Ben Solo.
Because Kylo reacted like this:
Luke didn't even get the chance to try to talk to Ben. And by the time he woke up Kylo had destroyed his temple and killed the students. There is no sequence of events where it would be plausible for there to be a conversation between the two OR for Luke to react like this with grace:
Like i said before bullshit writing. TLJ writers couldve written something better but they didnt. And they deserve the criticisms they get regarding the way they wrote Luke in particular the foundation of his conflict with Ben Solo. Its just not believable.
-dark thoughts and visions
-must kill nephew
-noooo
-*clunk on the head*
-mah students NOOOoooOOOO
-SHAME!
- Sorry Leia your on your own, even though your husband is left you (and soon to be dead), your genocidal son is still unredeemed, imma still gonna leave you and mop around some far-off planet!
- Save Martha!
- Why did you say that name
-Thats his mother's name!
Jedi master rank doesn't mean shit because these are people, not ranks that dictate their ability to handle severe emotional trauma. The stoicism of the jedi order was one of it's main flaws. "Just detach your emotions and trust the force." Yea no, most people are not capable of doing that. ESPECIALLY not Luke Skywalker. He could never live up to the notion of a TRUE jedi because he gives a shit about people. He's not Yoda.
Within the context of a family member being influenced by the Dark Side of the Force, i would expect post-RotJ Jedi Master Luke Skywalker to handle things much, much better than most if not all Jedi Master given his experiences in ESB and RotJ. Nebulous Force visions, Dark Side temptations, redeeming someone etc. Luke has first-hand knowledge and experience dealing with that, its costs and consequences . . . . that's why the conflict between Luke and Ben Solo as shown in TLJ was weak and laughable and undermines the rest of Luke's and Kylo's interactions.