I think a closer comparison would be Ronnie and Earl.
I think what sets Ronnie apart is that at any given time that the man choose to be #1 in his game, he was. In fact imho, he could be #1 right now if he wanted to be. That's not a knock against the best of the game currently. More so Ronnie's commitment to the being the best.
Agreed 100%. Ronnie O, just like Earl is a generational talent, but it can be argued that a few others enjoyed a similar run of sustained excellence. In snooker, that would be guys like Steve Hendry, John Higgins, and Steve Davis. In pool, it would be guys like Luther Lassiter, Shane Van Boening, Mike Sigel and Nick Varner that enjoyed the same kind of sustained excellence as Earl. That said, more than any of these, Earl had a way of beating the best players of his generation to a pulp when he was really on, just like Ronnie O.
Contrastingly, Efren is the greatest all around pool player that ever lived, probably the best ever at fifteen ball rotation, one pocket and eight ball, top ten ever at nine ball, and on that rare occasion that he played 14.1, he showed very good form. He could figure out any game played on a pool table and that's why he was a six time Derby City Master of the Table. He probably didn't shoot quite as straight as either Lassiter or Earl, which is why his list of major titles in nine ball is not as long as either.
Ronnie is much more like Earl or Sigel than he is like Efren, but maybe even more like Sigel, whose competitive intensity began to wane in the early 1990s even though he was still at the top of his sport. It's worth noting that both Earl and Efren named Sigel as the "toughest opponent I've ever played."