If your narrative was true, we would always see critics scores lower than the audience (assuming statistically significant number of critics reviewing a given movie). But we see so many counterexamples with radically different ratings: Spy kids, Ad Astra, Noah, King Kong (2005), Babe, The Blair Witch Project, Chicken Run, and thousands of others.
Not to mention a number of films who stopped the audience scores, decrying "review bombing". Some of these films were fine, while some were objectively bad (-cough- Ghostbusters reboot -cough-). I have a feeling (though it is unsubstantiated rumor) that there are payoffs in the critics circles for certain movies.
It's possible that those movies failed to advertise to the correct audience. If they pulled in people who thought they were getting 1 experience, but ended up with a different experience, the reviews are going to be lower than if they hit the right audience.
Critics, as noted, see everything and so they wouldn't be affected by bad advertising.
I've definitely been wrong, in both directions, about movies based on their advertising.
