This is what AOC meant when talking about how in other countries she wouldn't be in the 'same party' as many other Democrats. They'd have their smaller 'progressive party' and then they'd form a coalition with the "Moderate/Center Dem Party' and that would be a power structure.
Which kinda happened behind the scenes to help Pelosi secure the leadership previously when there were enough Progressive votes to block her.
Same as the GOP you wouldn't have everyone under the same umbrella... but America is and will likely continue to remain for a long time a two-party system because it's become far too established and financially secure in that model.