Hmm, RGamma describes reality: it is a fact that web browsers don't purely browse The Web, has been for decades now, and there is zero indication this is going to change.
You seem to demand that people ignore this reality, because you don't like it. This is not helpful.
I don't like this reality either, but despite that I find your statement also factually incorrect: "native applications have existed for decades, no reason to bloat the scope of a browser".
Of course there are reasons, otherwise people/companies won't do it, and users won't use bloated browser that give them no benefits.
I agree that downsides outweigh the upsides, but the upsides are obvious and immediate while the downsides are long-term and mostly subtle...