RINGO - bounced from band to band, becomes well-known host of pop music TV show. Always a tech head, was early investor in Apple and is still one of the 20 largest individual shareholders.
GEORGE - long term collaborator with Donovan and then Cat Stevens. Releases several solo albums to little commercial success. Leaves music for a period, but returned as Stevie Winwood's touring guitarist for 20 years.
JOHN - upon his release from prison relocates to NYC and co-founds the Velvet Underground. Convicted of leading major drug distribution ring, but claims he was framed by the FBI and flees overseas before sentencing. Last heard of location is in the jungles of Peru with Maoist revolutionaries.
PAUL - writes 15 to 20 number one hits for other artists. Brings Hendrix to England, produces the albums and is the original bass player in the Experience. Later forms a band with a piano player/singer named Elton and that band sells 100 million albums.
My point is that individually they all would have had impact, but there was something magical about when they worked together. They can't really be separated.