Firstly, to say Federer does not care about ranking is incorrect, he wants decent rankings becaus then he plays lower caliber players and plays less.  Had he not hurt his back in Montreal, he may have won the US open.  He clearly indicated that he felt he lost to Delpotro from a lack of ability to prepare due to the tweaked back in Montreal.  His plan was to play Montreal and Cincinnati to prepare for NY... his back thus prevented him from playin Cincinnati and to practice.   Too many tournaments, yes definitely so... thus they need to reduce how many tournaments players must play. Remember Fed can choose which he wants because at a certain age and certain minimum years on the tour, the players can choose to play less to keep older stars around to draw the crowds.
As for the empty seats in Toronto for the women's tournament, well that happens in many WTA tournaments, the women's game still not as strong a draw.  I will let you explain why the WTA tv ratings and ticket sales are lower.