I'm literally in charge of a team of 3 devs that does that. React complicated our stack, slowed things down both development wise and in terms of inefficient asset management, so we reverted to vanilla JS and never looked back.
What kind of app is it? Is it an SPA or a mostly-HTML website with some bells and whistles?
I've been through the whole gamut -- pure JS, jQuery, Backbone, Angular1, and React. I love React because it's by far the most pleasant experience for my work. You would not get me to go back to pure JS over pain of death, it's just a non-starter for the types of apps we're building.
If it doesn't sound incredibly painful your webapp isn't complicated enough to warrant a framework anyways.