The "si" joins the two nouns together.
English can very readily form noun-noun compounds where the first one modifies the second (sort of like an adjective) -- a "blue list" is a list which is blue and a "wine list" is a list which is about wine.
Turkish needs to put the possessive on the second noun of such a compound to get this kind of meaning, so "wine list" becomes "şarap listesi" (very literally, "wine its-list").
I think "şarap liste nerede" would make as much sense in Turkish as "Where is the wine the list?" would in English - just two nouns next to each other with no connection. And if you have something like "şarap liste görüyor" it sounds like "The wine sees lists" rather than "he sees wine lists".
(Perhaps this fact that nouns can often stand next to each other without being connected grammatically, due to the fact that the verb goes at the end rather than between subject and object, led to this kind of explicit connecting?)
It would not be correct. You have to also mark the noun being possessed ("listesi"). "şarabın listesi", as Maikefa below points out, would sound kind of funny and would imply that the wine bottle had a piece of paper attached to it with a list written on it, or something like that- the list that belongs to the bottle of wine.
Why would it be?
Şarabı is either accusative or possessed (his/her/its wine).
Neither makes sense here -- it is not the object, so it cannot be accusative, and it is not possessed, either.
And if you made it Şarabın listesi, that would be "the wine's list" rather than "the wine list".
All noun compounds will use the same form, as far as I know: first word in nominative case, and 3rd-person possessive suffix on the second word.
Duo's examples included "kuzu eti" (lamb meat) and "balık çorbası" (fish soup). All of these are concrete nouns ('non-abstract', as you said). The same would apply if they were abstract nouns: ex. aşk sefası = the joy of love
I'm wondering if by abstract and non-abstract, you possibly were meaning definite (specific) and indefinite (nonspecific/general)? Explaining it wouldn't really make sense with "wine list", so I'll switch to "window curtain", if you don't mind. We would use genitive construction if we were talking about a specific curtain belonging to a specific window (in other words, both nouns are definite, rather than the compound as a whole):
- pencere perdesi = the/a window curtain (compound)
- pencerenin perdesi = the curtain of the window (genitive)
I know you had to wait a while for an answer, I hope I understood your question and was able to provide one :-)