To some extent this is true that antivirus softwares are not that much useful , but we human dont have a choice , for example when we leave our home , we usually lock it , as precaution and to be safe , but the truth is locks can be broken or opened , same goes for softwares , that may be Android , Windows or etc etc . There is no 100% fullproof way neither there will be in future , but we can minimise the risk , as there is a saying "Precaution is better than cure " .