A plot above all the little segments? Some ideas, please reply!

I realised that the movie is about how time passes and how the relationships between people have changed trough the years. Some things that made me realise this:
-The first chapter is plenty of coffee and cigarettes, while in the chapter with the rappers, this is not anymore fancied. So happened in the previous chapter with the "cousins" Through the chapters, we discover how is it that tobacco and coffee have been devaluated and hated by modern society. At last, the ending chapter, the couple that again goes back to the coffee and cigarettes is completely destroyed: they're not young, they're not rich. They're the opposite of the previous couple with tea and not cigarettes was.
-The first meeting were practically unknown people who make each other a favour. The chapter with the rappers end up with the opposite: they play a trick on Bill Murray. So we can see how the rich cousin (Blanchett) tries to be nice and gives presents to her other cousin despite of their differences. This is an opposite to what happens to the another "cousins".
-The movie was filmed in a 17 year gap. Starting with Benigni and ending with the old couple. So does the set up change, going slowly from a bit oldie feeling (notice the jukebox) and ending with the rappers. The last chapter show the old couple lost and plenty of poverty in a world that does not belong to them, to the coffee and cigarettes generation, anymore.
-The repetition at some part of the dialogues are a reference to earlier chapters. This is so obvious. Tom Waits is a doctor, while one of the rappers is an "alternative medicine" student. Maybe a way Jarmusch is trying to make us notice things have become a bit more fake in order to be more cosmopolitan.
I saw clearly there was this plot, this message throughout the movie. But if someone disagrees or thinks I'm completely lost I'd like to know. I loved this movie!