> If they did something truly onerous

It would very unlikely be something which would affect Microsoft’s bottom line. They wouldn’t care.

> and everyone would switch their upstream to Edgium.

Who’s “everyone”? Anyone who cares minimally about possible shenanigans in Chromium is already selectively merging changes.

Edge aggressively sets itself as the default browser and slurps information from Chrome without permission. Edge and Microsoft are not and will not be a saviour from Google and Chrome.