> Great example to prove my point. They used a framework to quickly get something out of the door and working, validating the business idea, but later migrated away from it

They started migration 10 years after original release of the product, that's not PoC, that's way past that. Also, nowhere anyone said that they wrote their own framework/libraries or wrote anything from scratch, they migrated to multiple different tech stacks for their designated purposes, they might've very well used established frameworks(and probably did) later on.

I won't comment on the rest of your child-like responses.