Interesting idea. I am sure it would be easier to build on the moon or mars given less gravity and junk. I have heard of abother solutuon called orbital rings which is more practical on earth but requires a ring around the planet which may be difficult to build.
Space rings are definitely an interesting idea, but you're right, it would be a massive and difficult project to actually undertake! This kind of cooperation on a global scale would be a tall order right now, but as tech like blockchain moves us towards a more peaceful and interconnected society, maybe it won't seem so out-there in the future!
I tend to be more of a pessimist and think some sort of environmental disaster will push us to build them to make evacuating Earth easier. But I do hope humanity can cooperate someday to achieve further progress.