Sinister Supporter in his long analysis of the situation makes a rather elementary logical mistake.
"I like bread. I like sausages. Therefore, sausages are a kind of bread." The fact that it is possible to put the Wild Rover and Eleanor Rigby into a category together(or maybe many categories together) does not necessarily make them both folk songs.
And the number of people who say, as if it proves something, "It's possible for a new song to become a folk song so there" continues to amaze. Of course a song can become a folk song. That does not prove all songs are folk songs.Or that all songs will become folksongs. It merely says some songs may become folk songs.
But anyone can say what they like, of course. If your fond belief is that a folksong is a song sung with an acoustic guitar(or possibly a lightly amplified guitar)....well, carry on, it it makes you happy.That belief will just make it awkward when you are trying to discuss folk music with other people.