Apple is a closed ecosystem, so the OS that Apple builds is what goes into the end device. Android is open so manufacturers have the ability to add other privil

Apple is a closed ecosystem, so the OS that Apple builds is what goes into the end device. Android is open so manufacturers have the ability to add other privileged processes in addition to what is shipped with the default OS. These processes can monitor other processes and kill them in such a way that they can't wake up or display notifications until they are opened once by the user. These processes are usually added to extend battery life and make the device more responsive by limiting background applications.