Applaud the effort, and obviously I don't have the insight into the motivations behind the decisions, but I don't see this ending well.

Why have multiple SPA frameworks on a single page? What happens when one fragment is built in React X.X and another in React Y.Y? It feels like you have to pull a bunch of different pieces together to form what would formerly be known as a "route" in more traditional webapps, and I'm not really seeing the upside here.

I hope we get a follow-up in 6-12 months about where this experiment goes.