Unfortunately, a vast majority of WebApps are hot garbage and even the good ones can never be as functional or as performative as a native app. We have such powerful machines, but we relegate them to such a horrible method of using them.
Very few components are needed to make a bare bones web browser that is more of a vm. It would need one or more advantages over normal www browsers. Applications could be memory, and computationally heavy, it could store its data locally with some guarantees, it could run conventional web application on very crappy hardware. A new platform also offers countless opportunities to do new things or do things differently. That list is endless.
