There actually is some basic runtime support for generics, just enough to avoid breaking the runtime. For instance, if I create a class MyList extends ArrayList

There actually is some basic runtime support for generics, just enough to avoid breaking the runtime. For instance, if I create a class MyList extends ArrayList<Double>, there actually is some runtime information that says MyList is an ArrayList<Double>, not just an ArrayList. You're right though that saying templates are different from generics is based on opinion, not fact. There's no widely-accepted definition of both that would separate them as distinct from one another.