Not quite. WASM will enable faster web-based performance, but you're still building on top of a browser. If you're using the DOM, then you're still subject to the normal performance bottlenecks there, and if you're using canvas then you need to re-implement a lot of UI code.
React Native is layer on top of actual native components on the respective platforms. They two are wildly different technologies. I enjoy RN and I do look forward to WASM as well, but I don't see them overlapping anytime soon.