Mythos is relatively new and Antrophic has been fighting US government to not allow their models for warfare. However, it’s only a matter of time till they bend the knee and in next 5-10 years we’ll see the effects of that.
Previously US used rebel groups to throw governments in other countries that are not US friendly. In the future I can see they can just start chaos by attacking banking systems, energy infrastructure or any other important modern infrastructure until that country falls in line with US
That's all entirely science fiction though, until we see some actual evidence. If Mythos is so incredibly dangerous, then the models before should be at least a little dangerous, and we haven't seen that.