Perhaps generally, but not in all cases. I'm 40 yrs old doing a PhD. I've been asked by my department colleagues in their late teens/early 20's 'how is it that I know so many Canadian locals, when they started their PhDs before me and don't really know anybody outside of the University?'. It's because I had the life experience and confidence to go out and get involved with normal Canadian life. I've lived with Canadian non-students since I arrived 2 yrs ago, it's a criteria I had when I went looking for accommodation. Now I have a network of Canadian non-student friends across the city because of taking that approach, and I also work at the local ski hill 2 hrs out of town. The younger international students in my department only ever do things as a group, and only ever have social nights and get-together's with each other.
So I think it's very person specific.