True, but not in a way that matters precisely for the purpose of this discussion.
The issue as described in this article is the control of the single channel by one entity. The browser is an "everything app" in the same sense a television is an "everything communication appliance," but the signal you can put on it is sourced from thousands of different, independent operators (assuming, for TV, you have plugged in more than just a cable line).
In general, when companies that create browsers have attempted to reduce the browser to a single-channel tool (by, for instance, constraining the sites it will access), the browser has fallen in general-use popularity.
They're not though. In context an "everything app" is an application + service that bundles a bunch of disparate functionality. Such an "app" would only provide access to third parties that have some relationship with the app's platform. More like Disneyland than a shopping mall.
To be more precise, it is the combination of web browsers, HTML, JavaScript, and adjacent technologies that are the everything app, but your point stands. You are absolutely right.
Let's be blunt: the elevator pitch for the 'everything app' as «a smartphone application that will deliver everything to everyone on the planet» has already been solved. The pitch that Elon Musk and other tech oligarchs want to solve has an addendum, which the WebBrowser+ ecosystem does not yet[0] satisfy: «a smartphone application that will deliver everything to everyone on the planet [and is under the control of a single entity for its own benefit]»
[0] I say "not yet" because developing a new app from scratch is not the only strategy—see Google trying its best to make Chrome and derivatives the only useful 'everything apps'
