They were not so aligned until the 20th-century when Jews from all communities mixed again. I am not disputing that Jewish practices today and for the last two millennia are connected to practices in Judea at the turn of the first millennium and to texts that had been written even earlier. What I'm saying is that strict and regulated adherence by large parts of the population came relatively late. That, as far as I can tell from the research, is not at all controversial.
And even communities that are even further away like Ethiopia, Yemen, and India, are mostly following the same pattern?
Modern Judaism is very much connected to the state of affairs of ancient Israel/Judah from 24 centuries ago.