While I totally get your point, I don’t see this happening with the old guard. Stern feels Spike is the best architecture, for example, and feel no need to transition nor incur the costs associated with a switch.
“Cargument” incoming: You could apply the same logic to car engines. They all do the same thing, yet outside a few exceptions, they all continue to make their own engines vs collaborating.
Also, what you’re asking for already exists in the P-3-ROC, which supports multiple open source frameworks: https://www.multimorphic.com/software-development/
As the smaller, more startup-y guys get going, perhaps they move towards the model you describe, but I would not hold my breath.