Walt has changed even since then, and if he's able to avoid Hank dying, why not? I don't doubt Walt will avoid it if possible, but compared to Jesse, it would be an easier decision.When he was going to flee at the end of episode 11, he forced Saul to ring the DEA to tip off about the threat to Hank's life. He almost certainly saved his life.
The show is about Walt and Jesse's relationship. Their unconditional love for one another but how Walt emotionally abuses Jesse. And at some point, Jesse will snap. It's a great story and much better than any other path they could go down.