You could probably implement an online text reading system with basic markup and hyperlinks over a weekend, but the problem would be that nobody would use it because it would be seen as strictly inferior to the web.
I would want this "text-reading system" for example to have something like CSS. The difference would be that instead of creating ever-more powerful versions of CSS and Javascript, the architects and implementors of the text-reading system would pay attention to gotchas like the gotcha described in the OP (changing browsers so that what is copied into the clipboard is exactly the visible text the user has highlighted).
If at some point we had said "the web is powerful enough now, let's stop" then inevitably somebody like Microsoft or Google would have developed some other system that incorporated everything that the web does + extra stuff. In fact that's basically what stuff like Flash/ActiveX was in the late 90s.
Then gradually people would have switched to this new thing and the web would have gone the way of gopher and usenet.
Of course, if we could have redesigned the web from scratch right now with all the benefit of hindsight we could have (in theory) designed a better system. But as with most open things they rely on evolution rather than intelligent design.
I can understand your gripe, but I simply don't see how it applies here.
And that couple of maintainers would probably still have more important things to fix than what's essentially a curious but not really problematic bug.
My big point is that this is one of the many ways that the ambitious goals of the browser makers and authors of web standards screw up the workflows of those trying to use the web for reading and "allied activites" like navigating, scrolling and cutting and pasting.
These ambitious goals include assisting app developers and assisting design professionals (design professionals on the internet intersecting very strongly with "professional persuaders" on the internet).
Note that I am not saying that these ambitious goals are worthless or nefarious, just that maintaining a smooth and reliable way to share static documents over the internet is important, too.