The major reason for the never-ending disagreements on the nature of consciousness is that pretty much 100% of the time no-one ever rigorously defines what (things) they are actually talking about, and the word is so overloaded and poorly defined that any discussion therefore devolves into people talking about different things, as well as the discussion being so vague as to be meaningless.

There are of course other reasons too, with things like religious beliefs and human ego meaning that people come to the discussion with a major bias and fixed views rather than even being open to any rational discussion.

Finally, everyone is conscious and has an opinion, but only a tiny fraction are actually knowledgeable about the brain and have spent any large amount of time thinking about things like evolution and brain development .. they have an opinion, but are just not qualified to discuss it!

If you break down all the different things that people are referring to when they talk about "consciousness", and define them individually with as little wiggle room as the english language and underlying taxonomy of concepts allows, then I really don't think there is much mystery about consciousness at all, but of course those with an agenda who want there to be a mystery will still argue about every part of it including the definitions that remove all the wiggle room.

The nature of consciousness has long been a contentious subject, and one of interest, but it seems that the rise of AI has intensified the discussion with the new question being whether AI is or could be conscious. I do think this can be answered in a principled way (=yes), but in the end you can only PROVE that something, or someone else, is conscious if you accept a functional/testable definition of it in the first place.