They get resolved in order as you explained, but
en from en.google.com will only be resolved at Google's host DNS.
I defacto own any weird combo of third, forth, etc order domains that live under my registered second level domain.
So there is no way to do as you suggest in your original post with out substantially altering the DNS system by inserting one more layer into the public side.
I could rent ars.danthewelder.com to you, but I don't think that's what you really meant in your original post.
That isn't so. You don't have to change anything, you just add some more names for the root level servers to resolve.
Everything will work just fine, with no changes at all on the client end, and no changes in the servers, except maybe you need a bit more hardware in the root servers.
I told you - there is nothing at all special about any of the levels. danthewelder is just a name for the .com server to resolve, it could resolve any names, and .com is just a name for the root server to resolve - it could resolve any names.
For example there is no reason at all you could not have email at ars@com - just com, with no other part to the name and http://com/ could work just fine. There is no address set up for com, but there could be - those layers are not specially singled out.
If you sell person.slate.com to someone when slate.com is already sold to someone else, that means who ever owns slate.com cannot have their own person.slate.com subdomain.
Tell me how DNS is gonna figure that out from a string of text URL?
What you propose cannot be done with out taking something from the people who already own a particular domain.
They get resolved in order as you explained, but en from en.google.com will only be resolved at Google's host DNS.
I defacto own any weird combo of third, forth, etc order domains that live under my registered second level domain.
So there is no way to do as you suggest in your original post with out substantially altering the DNS system by inserting one more layer into the public side.
I could rent ars.danthewelder.com to you, but I don't think that's what you really meant in your original post.