Role of the megacorps in the late timeline

[AstroChara]

While looking through the timeline, I came across the description of the Age of Crisis, which has a mention of an event known as the Uservere Affair. Apparently Usevere was a major megacorp in the Mutual Progress Alliance which, when collapsed, created a crisis in the hypereconomy of the Sephirotic Empires.

This had me wondering about the role of megacorps beyond the rise of the archailects. What are they like? What do they do? Can they become important? What are their effects on the setting?

Also, what should we do about this and other similar incidents?

Opinions?