It's funny because nowadays people talk casually about binge watching TV seasons on Netflix, but if you mention that you played a game for 5 hours straight the same people often roll their eyes.
They're entirely different in many respects but no book nor TV show is essentially endless as a MMORPG is. If I spent 12 hours a day reading a novel I'd have finished it inside 2 days, similarly for watching many TV series. Yet I could spend 12 hours a day every day playing a game and continue until ... some external factor intervenes.
Books and TV shows don't have the same "reward" mechanisms (think Skinner box) they don't really relate as an experience other than that all 3 media usually involve a narrative of some form. Games feel like you're doing something worthwhile beyond sitting and consuming media as you do for a novel or TV drama; they give an illusion of achievement [often one carefully psychologically tailored to engage and retain the user as much as possible] that compels in a way other media do not.
Again, I can only relate personal experiences, but I've been just as compelled to read "just one more chapter" of certain books or to watch "just one more episode" of a TV series as I have to advance in a game.
I enjoy all three mediums and at different times in my life I've been into one more than the others. They all seem more or less the same to me (in terms of time spent, culture absorbed, entertainment value).
(I will occasionally watch a DVD, but maybe 2 hours a month, max.)
When people give me grief that I play the games, I tell them I'm a software developer: it's like a writer reading books.
I look at people in my parent's generation who have no hobbies, no outlets, nothing... They are bored individuals who watch the news and maybe do some gardening. I would love to breach the age gap and introduce a great uncle to a video game, or my great grandmother to scrabble online. I feel like the last generation that will ever go lonely unless by decision, and I owe it in part to these fantastical video games.
Gaming was my coping mechanism in the past, but I haven't played games for over 5 years now. It's merely a symptom, there are plenty of other coping mechanisms available.
I agree that time I enjoyed is definitely not time wasted. Playing with friends is just as good as programming to me. It's 100% unproductive though.
Mental illness is scary.