"Chromium would likely die if Google abandoned it."

I believe that is highly unlikely. At root the Blink engine is actively supported by several big tech heavyweights. Microsoft Edge is based on it. A rarely mentioned but important derivative browser is Silk (Fire tablets etc.) that Amazon develops. Then there are a bunch of smaller fish with Brave leading that pack.

I think the engine would survive just fine without Google. There was a time when you're view held, but that time has past.