I have heard this about the gambling industry, from colleagues when I used to work at an online gaming company. I think it is true that a large amount of the profits from these type of things come from a small percentage, and often those people cannot really afford to loose such great amounts of money either.
Of Zynga's games, apparently "less than 1 percent [of players] are responsible for between a quarter and a half of the company’s revenue".
When I was a teenager playing video games all the time, I had a great desire to develop them. Who doesn't? I think that was at least partly responsible for my learning to program. But as an adult, I'm a lot more ambivalent about the industry. Sure, it's art, and some games are awesome, but some also scare me. I can't shake the feeling that some games have a genuine psychological addiction element, and some people might not be well-prepared to cope with that rationally, and the whole thing looks kind of . . . exploitative.
I'm not as sure as I was, when I was 13, that I want to be a part of that.