I think you need to consider the difference between a browser, and the web dev tools that come with a browser. Let me put it differently, lets assume chrome has 10 billion users. Out of all those, how many do you think actually even know the dev tools exist? 10 billion? 1 billion? 100 million? No. More like 1 million.
Please take some time to consider what I'm saying to you.
That's an odd thing to say. Firefox, Chrome and Safari are absolutely web dev tools - they're the most powerful such tools I've ever used.