That's not the point, though; character progressions like that have to fit narratively with how the character has already been portrayed, which I would argue they haven't done with both Han and (especially) Luke. You can make these iconic characters vulnerable without going completely Jon Snow on them (strongest plot armor ever).
"“I said to Rian, ‘Jedis don’t give up.’ I mean, even if [Luke] had a problem, he would maybe take a year to try and regroup, but if he made a mistake, he would try and right that wrong, so right there, we had a fundamental difference."
http://collider.com/the-last-jedi-mark-hamill-on-luke-skywalker/#rian-johnson-disney
This entire discussion should be taken with the caveat that we still have one more film to go, and we don't yet know what direction they're going to take Luke in. I'd almost bet my house that he becomes a Force Ghost, though.