You, and the old people in your life, can simply stick to downloading from the official store. This change doesn't suddenly force you to live your life in a way

You, and the old people in your life, can simply stick to downloading from the official store. This change doesn't suddenly force you to live your life in a way that you're uncomfortable with. If applications suddenly drop out of the App Store (horrendously unlikely) and force you to install them via sideloading, don't do it. It's entirely your prerogative. Plus, I imagine Apple is going to make it quite involved to actually sideload anything. I think the old people in your life (incidentally, I know a lot more tech savvy older people than younger people, but that's neither here nor there) are safe from the nefarious clutches of added freedom.