He had decades to make further adventures of Luke Skywalker the reason it did not happen was because Lucas wasn’t interested. You read any interview after 1983 and all he talks about is wanting to do a prequel with young Obi Wan and Luke’s father. Then he spent 1994 to 2012 working on the prequel Era. In all that time he didn’t bother to write a screenplay for episode 7. And the sequel spoken of here is just a continuation of the prequels not of the OT. I’m also not convinced he did not whip this sequel treatment up very quickly to sell Lucasfilm to Disney as a sweetener, he spent years saying it was the 1-6 Saga of Darth Vader. Return of the Jedi was the end and there was no story.