Indeed, isn't six weeks longer then the between season break? This hasn't been done before so while we assume there will be some advantage to not going to the WC in terms of fitness (maybe down the line), it isn't clear cut. They will probably need some kind of pre-season to get up to the speed of the players who where in the later stages of the WC. Another odd factor is that players will be returning to their clubs at different times depending on WC (lack of) progress, so everyone will need a separate training plan.