[spmurrayzzz]

There's a greater issue that is often ignored here. If React is so large/complex that one ought not create their own version from scratch (I actually question this assertion, but will grant it for the sake of discussion), it begs the question as to how risky it is to bring into your stack. How trivial is it to replace if its so complex? Vendor lock-in can be a real problem for teams.

Remember the React license fiasco? What if Facebook hadn't caved there and removed all the controversial patent language (by relicensing as MIT)? What if, as a matter of existential risk, you had to make the business decision to remove React from your app?

As such, I think the other component of this particular decision tree should include how much you become dependent on a particular library/module/framework and the consequent risks that introduces to your organization.