Miss world vs. World's Mis

How would you answer this your student’s question? ( as an EFL learner)

“Why we say Miss World and not World’s Miss, and accordingly why we don’t say Light Street, and we say Street light” ?

Adjective before noun, title before noun. Same-same.

Light Street might have a street light on it, though.

Thanks, and what about “World’s Miss”? [ can we say that you’ve answered it when talked about Titles before nouns? ], if so, then it’s OK, but the student wants to know why s/he can’t say World’s Miss meaning the same as Miss World?

Yes: titles before nouns.

Mister Right, not Right’s Mister.
Captain America, not America’s Captain.
Doctor Hibbert, not Hibbert’s Doctor.

English is generally left-branching for adjectives and adverbs but right-branching for prepositional phrases and other complicated things. A street light is a kind of light, not a kind of street. A road called Light Street is a kind of street. Titles aren’t the most adjective-like of modifiers, but they still go to the left of what they modify. (There’s probably no inherent reason behind that, aside from it’s just the way English does things. In Japanese, which is the textbook example of an exclusively head-last language, honorifics like ‘-san’ follow the noun they modify.)