What do you want that is not being given? I'm reading thinking, "Wow, two nights a week. That's a lot of time. Probably can't keep that up indefinitely if they're maintaining separate households."
Short communication, I agree, does not a relationship make, but you do see each other regularly. That is what makes the relationship. Some people are low level communicators when not face to face with someone. I think that's more personality than interest level sometimes.
If you're hearing the words "don't want to look too far into the future," then, my opinion, you're getting a clear message. They don't want to disappoint you, but already realize they might. Your vision of poly may very well not match theirs, but it doesn't necessarily mean they're not poly. Try not to view it through that lens. When you find yourself facing those differences in relationship style, personality, communication levels, etc., then the question, I think, you really need to ask is, "Are we receiving enough benefit in the relationship to make it worth the effort?" If the answer is yes, then you may want to ease up on your vision and let the relationship be what it will be. If the answer is no, you can try easing up on your efforts or even let the relationship go. There is no shame in that. Every relationship risks failure. Polyamory doesn't make every relationship viable, and sometimes love isn't enough to make up for differences. But how long you give it really depends on how you answer that question.