I don’t think you can sustain a career across so many decades and have an influence on such a variety of artists without being counted up there as one of the “greats”.
He has rarely done anything which could be considered mainstream (whatever that is) and, sure, there are better vocalists, guitarists and lyricists out there, but his career speaks for itself and needs no justification from anyone.
I’ve got a lot of his albums - though by no means all - from across the years but the one I keep going back to is Goldrush.
I have most of Dylan’s albums up to Blood On The Tracks and rarely listen to them. I listen to NY regularly