I have been playing bass for over 40 years and I used to think that Paul McCartney was a mediocre bass player at best. I have just watched a series of very early Beatles concerts, and can now say without a doubt that this man is a bass genious. In those days I was a fan of Cream and I thought that Jack Bruce was the best bass player in the world, but I have finally come to realize that Jack Bruce was and is a very good blues bass player, but back in those days, Paul's bass actually carried the band during live performances because Lennon and Harrison's guitar parts could not fill the melody lines the way that McCartney's bass lines did. Just a pretty significant realization that I have just had watching old Beatles concert footage. John and George were pretty much playing chords and George the odd lead part, but it was Paul's bass that provided the emphasis in the songs where it needed to be.
Just wanted to share this.