This kind of language change can't really be accomplished by fiat, so it makes sense to look for the direction the language is heading in and push. More and mor

This kind of language change can't really be accomplished by fiat, so it makes sense to look for the direction the language is heading in and push. More and more we see people using "they" as a singular pronoun. But a large proportion of people find this usage strongly ungrammatical, which is preventing it from becoming mainstream. Eventually it will win out though.