I think that's really what they were trying to showcase, personally; no matter what happens or comes between them, it's all about one thing -- family. And then you have the juxtaposition of the Byrde's who sort of get out "unscathed" but the Langmore's obviously lose everybody and everything. Well, except for Three, who I guess is basking in his new found riches and has a pretty damn cool new pool.
Felt like they kind of had points in the past seasons where Charlotte was the annoying, whiny kid and then it transferred over to Jonah down the final stretch. The car crash seemed to be the turning point which ultimately brought all of them together and put into perspective how fragile life is and what they mean to each other. As if constant dust ups with cartel members and psychotic Ozark hicks wasn't enough, but alas.
Jonah being the one to step out with the gun and essentially fend off the PI from the Byrde family is definitely a full circle feeling. It's kind of the final chapter that they are all together as one unit which I believe was the main point the writers were trying to drive home. Casino money, cartel death, etc. --- ups and downs-- they will always have the Byrde clan.