There have been multiple webview-using equivalents through the years. A big part of why Electron-likes have succeeded so widely where those did not is because

There have been multiple webview-using equivalents through the years. A big part of why Electron-likes have succeeded so widely where those did not is because they suffered from absolutely massive fragmentation, both in features and in performance/bugs. Electron (comparatively) does not, because it bundles its own full stack. You have to deal with upgrades to it when you choose to do so, but not "everyone simultaneously has a different version of their webview, many of which you have never seen and cannot reproduce, and you always have to deal with them all".