Frankly I don't care about Federer's relative decline. He has won everything there is several times over, Federer is the one player where another title wouldn't add much to his career. Further, Federer is a freak of nature, being persistently injury-free while maintaining in his early 30s a spot in the world's top 3 and being competitive with much younger players of the calibre of Nadal, Djokovic and Murray. Aesthetically his tennis remains unique anyway, there has not been a player who I have enjoyed watching so much since John McEnroe. I treasure every day Federer continues to be around.
Spot on. plus he loves playing for playings sake, loves testing himself against younger players at the top and enjoys travelling around the world. Doesnt have anything to prove, and only adds to his records with every match he plays it seems. so no reason to retire and long may it continue, especially for fans who like watching him play.