I think one needs to look at the differences between the value of Lennon's estate and McCartney's and see how the money was used and invested. McCartney did have the added benefitted of many more years of touring and generating product than John did. I don't know if blame is applicable here. As an artist he was successful at a numbers game some others were and weren't. I don't think the wealth gap can be worked out on an artist's back.