React trades simplicity of certain things such as dom manipulation, and makes it difficult to fetch external (ie noncompiled) html and include it as react dom nodes, and ad serving is pretty difficult too because most ads use document.write and this paradigm doesn't work with react, as well as single page applications and the rendering of contextual advertising requires server-side rendering too.

State management solutions like redux; nobody i know or have seen does it exactly the same, its really tricky to use and takes a long time to get the hang of.