But to answer your question, computers are no longer a hobby, everyone uses them, at least in the developed world... As some one said, it's like cars, or mobile phones or refrigerators.
I think that the comparison with cars in particular is very apt. I use a car every day but I don't care about cars at all, to me they're just a thing to get me from A to B.
But other people I know read car magazines, attend car shows, watch car-related TV shows, participate in car-related online forums - whether vintage or modern. For them, cars
are their hobby.
The fact that most people who use cars don't consider it a hobby, doesn't mean that it's not a hobby for some people. Isn't that the same with computers?
EDIT: And I guess the question is, now that computers (including tablets, smartphones etc) are mainstream, are there more or less people for whom computing is a hobby compared to the '80s? My guess is that there are just as many, if not more.