Why wouldn't I save my booster up in case the next strain is extremely dangerous then? Why are they not explicitly saying the amount of days to wait until gett

Why wouldn't I save my booster up in case the next strain is extremely dangerous then? Why are they not explicitly saying the amount of days to wait until getting it? Friend went to get a booster, the medical staff asked them which one they wanted. Not, here's the best advice, what do you choose. They refused to say which one to get. Why do people think this is normal? Or acknowledge this is abnormal then allow it to be put into law and treat the antivaxxs like garbage. We have millions of data points by now. All this is not acceptable.