It is true that a web app needs a browser. But a native app needs an operating system (OS). Something that I find fascinating though are apps that you can boot into, eg. they do not require an OS. But if you want graphics, mouse support, play sound etc, it becomes quite complicated. Compare that to a web app where you get all that functionality for free, with no libraries needed. And in between we have the shared lib utopia with Debian et.al and dll-hell with Windows. Each stack have their advantages and disadvantages. I however don't see bundle sizes on the web as a huge problem, at least not yet. With service workers you can download the app once, then even use it offline. Everything is just one click away and can be reached via an URL. And if you stick with "vanilla" it can also be fast and lightweight.

Wait, what?

So you think a kernel is large and has to be counted in the total, even if a browser also requires a kernel.

Yet you think web apps don't need libraries, so you are not even counting the browser and its dozens of libraries?