Speculation: Following the Silence of Sentry, MarsCo as a corporation is hobbled. The Big Three are faster and lighter, and use the 10-20 years of blackout to draw resources and personnel from their parent corporation. The new corporations are more thoroughly vector-owned and strongly allied as the “them” in this “us and them” conflict, though this alliance largely breaks down by AE70.
Reference:
Date Notes: After Marsco’s AI is partially shut down, before Subsidiary spinoffs