Also, while Fox News performs well in the ratings with right-wing pundits, it's increasingly becoming less profitable to run conservative commentary shows because of the toxicity tied to their content.
Once Fox News decided to go down the rabbit hole of using racism as a propaganda and fear tactic, they've been losing sponsors left and right for their prime time shows. The only reason why they haven't changed course is because of the audience they're able to pull. For some reason though, Fox is not valuing revenue and trying to balance it with the audience: instead of being seen as necessary equals, audience trumps revenue for them. When any other network realizes its programming is unprofitable, they would dump the content that's not working in favor of something else.
OANN likely is being passed by major advertisers for the same reason as well as for the bad reputation it gets for commentary that is absent logic and reason, to put it nicely. For CNBC to go down that route would end up resulting in the network not being able to, as one of its slogans says, "Profit from It" down the line.