When things collide, they transfer their movement energy. If things collide like this >- They will continue in roughly the same direction. If they collide like this -> <- their movement will cancel out and they will fall into the sun.
Satistically, at the “beginning of time”, in a random sphere around the sun, things will not be completely the same. So everything will either collide and fall. Or it will collide and continue in roughly the same direction. What we have now are the leftovers that were moving in roughly the same direction and colliding so little that they didn’t fall into the sun because of that.
The same is true for the “disk”: If you start with a roughly evenly distributed sphere of gases or something, there is a middle somewhere where there is a little bit more mass than anywhere else. That’s where things will go.
I don’t think that there is an obligation with that kind of standard, no.
Banking and security, accessibility yes.
Specific choice of “user side software”, probably not. And it’s somewhat unlikely to happen too, because if you think about apps on phones, if suddenly a completely new phone OS were to show up and had 30% market share, it wouldn’t make sense to have a law that would legally require them to offer an app on that platform
And Chrome isn’t “officially bad” in a legal sense.
The internet standards themselves are a bit… imprecise too. Implementing them in browser is ultimately up to the companies, there is no legal body requiring a browser to have or not have features. They just usually sort of do the same things because going different paths would be stupid. Mostly. Sometimes they totally do that, though, e.g. calendars and contact info have a standard, but all implementations are a mess and transfer is a pain.