Do films have to mimic life? No. Do some filmmakers choose to have that happen? Yes.
Yes, but most of the time movies that mimic real life are comedies. A supposedly “serious” movie doing that kind of stuff is just weird and awkward.
And can we not say characters were flat in Last Jedi when there was no character development present at all in Force Awakens? C’mon now…
That’s why there needed to be more development in The Last Jedi. The characters were flat in that movie because they were also flat in The Force Awakens, and Rian had no clue how to expand their stories in a satisfying way.