It's an interesting question because there has been a dominant narrative that back when there were only 3 channels and everyone trusted what Walter Cronkite said there was a lot more consensus.

That was true in the sense that centre-left and centre-right points of view were expressed on all networks (by law because of the fairness doctrine), also because the cold war gave a broad framework for crafting a consensus within, consolidation of newspapers left only 1 or 2 major newspapers in most markets, and because the two parties were each much more ideologically diverse. There was a consensus, but it bounced around the centre, and on topics where there were large disagreements usually you could still count on people to at least be able to articulate the countering sides' views and why someone might hold them. There was a greater appetite for trying to figure out an issue by hearing the best arguments from the other side (watch old episodes of Firing Line on YouTube to get an idea of how it was).

When climate change first became an issue in the late eighties there were a wide range of opinions on it, even though people had no more expertise on the subject than they do now. But people had less confidence that their views were right and people with contrasting views were deplorable or had a secret agenda. Even in early naughts Gingrich and Pelosi did a commercial together about how it was an important issue [0], even though there were pro-growth republicans who didn't want to take action, and pro-labour democrats who wanted to preserve working class jobs that disagreed with them. It was more common to see someone's opinion move in the course of a conversation because the culture war lines weren't so sharply defined. Politicians also had less to gain by exploiting divisions because the structure of the political system rewarded politicians who could pull voters over the centre line instead of just firing up the base.

More than anything it was more acceptable to have heterodox views. You could be a pro-choice republican or pro-life democrat because on the balance you had more things in common with the party of you choice than you didn't. Did everyone have quixotic or unique views? No, but you didn't have to self-censor as often if you did. It was a lot easier to be intellectually curious and learn things from others.

The theory at the time was that the 500 channel universe and the internet would break the old consensus and there would be a whole universe of opinions available. But it seems that "the big sort", the weakening of the parties and strengthening of PACs through campaign finance reform, the modern primary system and how it allows activists to influence and take over the parties (which is really only 40 years old), filter bubbles and people discovering that they prefer not to read stuff they disagree with, and algorithmic newsfeeds that optimize for engagement (ie outrage and out-group homogenization)... all of that has formed 2 consensuses that are more doctrinaire because they are so clustered apart from each other.

It's increasingly uncommon for people to have many or any friends with different political ideologies than them. 50 years ago a majority of Americans said they would not be ok with their child marrying outside of their race now the vast majority are ok with it, but inter political marriage is the exact opposite with it becoming increasingly uncommon and socially unacceptable.

I tried to follow a range of non-political commentators over the last year, and always thought that lab leak was a hypothesis that couldn't be ruled out given what we know, but made a zoom birthday call go silent when I voiced that opinion because everyone on it was sure that only a right wing loon could consider such a thing. While there was persistent coverage of the hypothesis in alternate media like the Dark Horse podcast, and posts on medium by postdocs sticking their necks out, the liberal media seems to have committed epistemic closure on the topic, with the NY Times COVID reporter just yesterday bemoaned the hypothesis's "racist roots" [1] (despite, as Greenwald points out, that the wet market theory sounded a lot more racist than a mistake at an NIH funded lab). Even the NY Times' previous COVID reporter tried to excuse his blind spot by falsely claiming that the hypothesis was confined to right wing kooks. [2] Of course it's no more racist to blame the pandemic on a mistake made at an NIH funded lab than to blame it on wet markets, but once the lines were drawn it was more important to score short term points against the other side and never admit that someone like Tom Cotton, might have made a reasonable point.

[0] https://www.youtube.com/watch?v=qi6n_-wB154

[1] And the fact that she calls it a "theory" should discredit her as a science reporter https://twitter.com/ggreenwald/status/1397623499888463872

[2] https://donaldgmcneiljr1954.medium.com/how-i-learned-to-stop...