Be aware that Roku doesn't make apps for those services or for most services. The services generally make their own apps (perhaps through a contractor). Those three make their own apps. Some, such as Fox News Channel, are also available as part of another service, such as Sling TV, YouTube TV, etc. If they were dropped from that, it would be the specific service that dropped them, not Roku.
Roku would have no incentive to drop any app that made them money. For example, you can subscribe to OAN via Roku, and Roku gets a cut of the subscription. That's money in their pocket. And while NewsMax isn't a subscription service, an app has been available for Roku for years.
It's extremely unlikely any of these are going anywhere, and even more unlikely that Roku would drop the apps.
Roku Community Streaming Expert
Note: I am not a Roku employee.
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