system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars ROTJ] If the Rebellion had been crushed and Luke had joined the Emperor wouldn't he have been worried that a new young full bodied Sith would be after his position?

It's like he knew where he was with Vader but with Luke he would have had a real rival for the first time ever. So why risk it?
gpt
Oh please. The Emperor never saw Luke as a threat, and for good reason. Here's a boy that got to train with an old fart for about eleven minutes (keep in mind that Yoda was an unknown contributor to Luke's development). Luke got lucky one time, then proceeded to get his ass whooped and his hand handed to him the only time he'd been pressured into a duel.

At the time, what mattered most to the Emperor was claiming the boy. From his perspective, he'd have plenty of time to develop him into what Anakin should've been.

Also, yes. Absolutely. The Sith are perfectly content being nipped at by their students. That's how their power grows.