Users don't tend to "accept/reject" installing new apps. Only techies understand that to be an option. Others just follow the flow. If the installer is asking them to do it, they will do it. If in order to use Facebook they have to install Instagram, WhatsApp, Messenger, they will do it. We will get to the same level of easiness in time.
Not sure. My mother (boomer) for example during installation added a bunch of apps, but then asked me "wtf are these, pls uninstall". So in the end the result was not achieved.