It doesn't matter what makes them different; it doesn't even matter if the only thing that makes them different is the way they are made possessive. The rules are clear even if why they are rules (or should be) isn't. What is equally clear is that you are not following the rule(s), which means you are not only not right, but wrong.



Well, yes That's kind of the whole point. So until you convince the majority of the public and scholars to adopt your treatment of possessives, you'll remain wrong. Furthermore, your readers will have to spend extra time (negligible though it may be for each individual instance) deciding from context whether you mean a word to be plural, possessive, or whether you've simply made an error. And you'll give the appearance of someone who doesn't know how to write properly, which you're obviously fine with.