Who knows how long it will last, but I expect it will be another 3 or 4 years atleast. Raonic and Tomic are 1 slam calibre players at best IMO. The rest of their age group arent even worth talking about. Maybe the generation after that will hold more promise but people I have talked to arent impressed with the current juniors either. The next really good generation will come at some point but they arent on the near horizon of arriving either. The lack of any decent up and coming talent has been a trend for a number of years now. Donald Young was the youngest player in the top 100 and had never lost to a player younger than him only a couple years ago. Donald freaking Young!