I don't think the plural of person is people. I haven't checked my dictionary, but, shooting from the hip, I expect to find the plural of person to be persons.

But this is still an interesting point of grammar. Would the word people ever take a singular verb? I can't think of an instance when people would take a singular verb--it sounds very grating on my ear in the few sentences I just constructed in my head. Collective nouns have always raised so many interesting problems in my mind, at least.

Best regards,
WordWethePeople