Being that maariv corresponds to burning of parts of the day’s offerings, why does mussaf not qualify for tashlumin on account of ונשלמה פרים שפתינו?
All teffilos nowadays are ונשלמה פרים שפתינו, nevertheless in order for the tefilloh to be considered like a korban it has to be brought at the correct time. Mussaf does not have a tashlumin because tefilas mussaf is for the korban mussaf, and if that time passed we cannot make it up. The other teffilos, which are said for the korban tamid and to plead for mercy, those teffilos can be corrected at the next teffiloh.
O:CH 108-6 Magen Avraham -9, Taz 4.