I was part of a team building a complex web gui. We started the project in 2015. The GUI had a _lot_ of cascading business logic, an editable high-density grid, all kinds of fun.

In our tools evaluation, React just had too much overhead. changes would trigger a huge cascade of events that killed responsiveness. We went with Backbone and it served us very well.

I know React is king, but so far I have managed to live without it.