I might get downvoted for this, but I think it is an important point to really consider. The claim that the web is getting/remaining open is somewhat dubious. As JavaScript and web browsers get increasingly complex, it is harder for anybody to just start up and write a usable, compliant web browser from scratch, which in fact entrenches the status quo.

And why do we simply trust the existing browsers? Google has very specific goals to monetize you and Chrome can be leveraged to help that goal. Microsoft's historic fight with the web and now their current changing business goals are a reminder that their web browser goals can always change, and their current model seems more like Google. Apple is always Apple. And why should we blindly trust Mozilla? They depend on external funding to keep the foundation going to pay for a lot of the complex engineering that goes into Firefox. I'm not accusing them of anything wrong, but you can look up prior controversies about their funding sources and decisions and see people don't agree it is all rosy.

I'm suggesting the increasing technical complexity is not necessarily working towards the goal of an open web because it is entrenching the gatekeepers that can make the web browsers.