I read a funny story about a kid in a class struggling to answer what the picture next to the i was... and even with several hints and then the answer, the kid still had no idea at all what an iron was.
I think with the popularity of knits, they're completely optional in a lot of people's lives.
I currently don't own an iron but I would only use it sparingly. Probably more for crafts and science projects than clothes. I have used the unwrinkle sprays and generally like the way they work.