It's a good discussion but defining great for contemporary artists is very subjective and personal. After fifty years, give or take, it becomes less so because history will judge for us, but to judge current artists is always going to be personal and hence turning it into a competition feels pointless to me. Take the competitions we hold here - my choices have never ever won, or even been placed, but I know my votes have gone to the greatest songs because I'm right and anyone who voted differently is wrong
...so it proves competition is not a valid way of determining greatness.
This discussion seems very pop music based, and also very results (i.e. sales) orientated and I must say I don't see the correlation. Just because one songwriter is at the top of the charts and another is in their bedroom doesn't mean one is a better writer (it
could mean that, but it's not a given). There are so many other factors - time, luck, looks, geography, payola, pushy parents, famous parents, parents with the money to trot their kids round dance and singing and acting classes, desire, chosen genre (it goes without saying that folk and blues and fingerpicking acoustic are the most noble of genres and pop song-writing doesn't even come close...
) and so on. So for me, record sales in the charts are an irrelevant measure of greatness.
I have nothing against Taylor Swift - I've heard a few of her songs and they were pleasant enough, but none of them made me want to go out and buy her records. But then I'm not her target market. I'm forty years too old. There are, however, songs that I've heard
on this very site that I would go out and buy - I can recall half a dozen or so absolutely outstanding songs, and I've only been here a few months.
For me, those are better songs than most current pop songs that I hear on my commute. Simple as that. The songs here that I'm referring to make more of a connection with who I am, where I come from, what I've seen and done and so on. That's what great song-writing is (again, to me, YMMV) - it's about touching people, moving people, making connections, building emotional involvement, and that's why a twenty-something year old girl is going to appeal to some people and a fifty year old man is going to appeal to others. They're potentially both great songwriters, but they're both great to a different set of people.