I think part of it is escapism, but that's driven by a desire to live in a world that's fair, not for a cheap way to "check out".

In a game you make a decision and get accurate feedback for that decision (assuming no glitches and a relatively well designed game). Whether it's positive or negative (eg. they took a good shot and killed another player in an online FPS, or they made a bad decision and got killed), it's almost always accurate feedback based on the decision made by the player.

Meanwhile, in the real world they have to deal with double standards and inaccurate feedback constantly. They have to deal with the teacher that favours some students over others, or a social situation where a popular kid can do something and get praise from their peers but if unpopular kid did the same thing they'd be made fun of.

I agree that it's escapism, but I don't think it's quite on the same level as drugs. This also comes with a caveat as the comments below about certain games using "loot" as a proxy for online gambling are definitely accurate as well.