I remember Dances with Wolves and Goodfellas both doing well with critics. Is there a link to contemporary reviews ?
Rotten Tomatoes publishes old reviews.
But yeah, Goodfellas was, and is, the critical darling whereas Dances was very much the more populist pick. Also, Goodfellas is by one of the definitive 70s auteurs, Scorsese, and would fit right into that decade. It’s quite a bit ironic to cite it as an example of critics getting it wrong and 70s movies being bad.
Edit: also, I want to address this ridiculous notion that critics are just a bunch of snobs who don't like popular movies. Go look at Rotten Tomatoes, and you will find that every single one of the fist 20 or so films in the MCU is rated "fresh" by critical consensus, and a number of them are over 90%. Toy Story 1&2 are at 100% positive reviews. If a film is good, it gets good reviews from critics, regardless of whether it is a tentpole film or a franchise blockbuster.
It's true that they also give reviews to a lot of low budget and independent films, but many critics feel that they have a responsibility to bring attention to films that audiences tend to ignore. In fact, many claim that one of the best things about their job is when they help bring attention to a truly new voice. And I applaud them for it.
Critics watch a LOT of movies, and most have studied and written about film their whole lives. Art is subjective, and I disagree with tons of reviews. But on aggregate, they get it right most of the time. It's almost like being an expert has value.