There are some similarities with Tiger and Federer but some don't hold water. The main is that as Federer got older, new great players arrived in Nadal and Djokovic. However, the main reason he is no longer winning is his age. Tiger is still in a prime golfing age while Federer is old for a top tennis player. But Tiger has to deal with the new blood like Rory, the late emergence of Adam Scott, Bubba, Dustin and others.