The problem is that the teams don't have a lot of preparation time for this tournament. Otherwise you could fly to Qatar 3 weeks in advance and then you could prepare optimally there to also adapt to the weather conditions. For example, if you play football in England, France or Italy in November, it can already snow or freeze. Quite strange when you are in Qatar 2 days later on a training field and that it is 32 degrees there. Your body has to get used to that too. What many people don't realize is that you can get a reverse version of a kind of flu due to the extreme temperature difference. If players go home, you can easily catch a cold again in December.