I don't think entertainment is really a waste of money, it's just that you have to consider more carefully where you spend sometimes. Often I hear very classist rhetoric about poor people buying an Xbox or iPhone. Are these necessities? No, but they are very important investments for the person, not in their financial future, but their happiness. $1000 for two years of greater happiness isn't that much. Compare that with a night out of drinks or a concert and you realize which is more expensive.
I think the greater issue is that many are devoid of both happiness and money. Despite the old phrase, there is a very clear link between the two in modern society. If they were the happy dirt farmers told of in tales by the rich, then they wouldn't feel the need to buy things they supposedly don't need to have a more enjoyable life.
It's of course a lot better in certain countries than others.
But sometimes you have to make the trade of some happiness in one form for greater security and happiness in the future.
RE: Is investing a luxury, or a necessity?