A lot of the explanation was made in other replies, but it didn't touch on all of it.

As civilizations peak, relative abundance and safety make people weak. The hard won lessons and hardships their ancestors went through, at the peak of civilization, their progeny become accustomed to, take for granted, and demand more and more. The people become spoiled, selfish, and hedonistic. The economy begins to center around providing more and more excesses and pleasures to cater to people's pursuit of more and more dopamine hits. In that state, and in that environment (what we're currently in right now), it's very easy for people to become slaves to their desires. They become addicted. And, with the instant gratification of modern society, impulse control is at an all time low, as people can often get their dopamine hits almost immediately, or within 30 minutes, max.

Video gaming is no different than any other vice being offered in this highly hedonistic society we're currently living. If you've never seen any info on addiction, you should. It explains a lot, of how people act, how they rationalize their choices, and how it becomes an ingrained behavior and mental attitude, that is really easy to fall back into.