Film is a collaborative medium though so comparing Lucas to the Beatles isn’t quite fitting (for that and many other reasons). Plus Star Wars was built as a pastiche throwback that added onto existing myths and genres, so it seems perfectly natural and fitting (moreso than even in other franchises) that people would take up the tradition and continue the series without him.
(Which is to say nothing of the fact that the last three [four if you count TCW] SW movies the man made are nowhere near the quality of the four that have since been made without him.)