I'm assuming it because the Empire was a government, and it was clearly presented as a government with governors, a senate, diplomats, and subjects. Autocracies are still governments that collect money and/or other resources from their subjects (or outsiders) in order to function. They can't conquer further territories without existing resources and support that normally comes from their citizens. Don't forget that many autocrats including Hitler had a large degree of public support too. Also, in the case of the Empire, it originated from the Galactic Republic, and there's no reason to believe it completely abandoned whatever economic system they had, which did involve trade and taxes as we saw from TPM.
So yeah, I think it's a safe assumption.
But what about the First Order? All we see and know of regarding the First Order is the military. That's it. Correct me if I'm wrong, but we haven't seen or heard of any other type of political leadership besides Snoke, which is probably a big reason why people ask, "What are they supposed to be?". To further complicate it, there is also the New Republic, which is supposedly this new government that superseded the Empire. We saw that they had a capitol, subjects, and at least some degree of public support. But again, does the First Order have any of this? Do they have subjects? Do they have anyone actually supporting them? Where do they get the money, weapons, soldiers, officers, ships, etc. especially if the New Republic is what superseded the Empire? The Empire had a senate that originally supported its creation with "thunderous applause", but what does the First Order have for support?
Maybe this will be addressed in The Mandolarian, but if so, it's a disjointed method of story-telling.
But if there are, they're not exhibited in the movies. The prequels kept reenforcing this idea of Jedi versus Sith and that there can only be two Sith at a time. Yet the two Sith were destroyed at the end of ROTJ..... so where did Snoke come from as he's also clearly not a Jedi? It's jarring having a character like this introduced despite what was already established in previous movies.
And I'm in the camp that does not want to read these young adult style novels to understand the story in the movies. I tried one and had to quit since the author seemed to struggle completing a full sentence and could only write in clauses.