What is more important is: is it working? And if not, why not?
Because, per the linked research, in present-time USA that weight is ~zero.
Which is especially interesting considering the USA's narratives about itself. And how, it seems to me, its population is so invested in said narratives that it will defend those even in the face of contrary research. You'd think a culture so invested in its self-determination would be angry about this result and endeavor to do something about it.
In Slovenia or Denmark, there may be two degrees of separation fewer between the regular voter and, say, an ordinary MP, because the parliaments and government are about the same size, but the population is in single millions. Even here in Czechia quite a lot of people actually know personally some high-ranking politician.
How many Americans are on friendly terms with their Rep or Senator?
I would imagine if you limited this to folks with $100MM+ net worth, the percentage wouldn't be so low.
It is pretty safe to say that the US could be more democratic. It is probably reasonable to compare it to other countries in terms of how democratic it is. But saying it is "not a democracy" is a fairly trivial observation. Republics aren't technically democracies if democracy means that the people make the decisions and win on all the disagreements. Republics are modelled on places like Rome that had a very visible and powerful oligarchy.
This statement applies to absolute monarchies as well; we have many examples from history where the people have "really put their foot down" and won concessions from that form of government. I don't see how this is enough to call the system democratic.
In the US the people can, formally and legally, do pretty much whatever they like if they vote for it consistently over the course of about a decade.
It's always “working”, the question is for whom.
I still think about the Bonobos a lot.