There are a lot of cities and countries with names ending in s preceded by a vowel, but very few with a consonant preceding the s. Examples: Netherlands, Brussels,New Orleans, Cowpens SC, Solomons aka Solomons Island (without apostrophe) MD

If I am right and my list above is nearly complete,why are there so few?

Also in most of the above the s at the end sounds either like a possessive or a plural, but when preceded by a vowel, for example, Annapolis and St Louis it does not suggest a plural or a possessive.

(Or is it my imagination?)