Ok my definition of Gamer is very loose, more specifically I associate Gamer with someone willing to pay any game. The guys who take on systems and use or possible abuse it to achieve certain results.
"You can't do that in level 1" is something the GM would say, and something opposed by the player. In what I think of Hard Core Gaming, I think can a gamer take all those things he learned through gaming and push the envelope in what regular people would think unlikely or impossible.
Its that expectation that you can't because of the way the rules are set up, but the possibility that you can because of how things can be made to fall to place.
"You cannot do that because of your limitations: economic status, social status, background, training or education" are very general assumptions. It is in the details where a Munchkin thrives, the little bonuses and multipliers that add on temporarily (because it is a temporary loop hole or you can only excuse your self once). Small Hacks to get one by long enough till resources come in, the cavalry arrives, or possibly Leveling up.*
There is a trade off living the comfy and familiar gamer surrounding to that being in the battle lines: because your mind, as much attention as possible has to be in the game to predict, execute and adapt as quickly as possible one has to surround oneself with the material. The way our RPG books fill a wall in our private space, so does the Game rules of work.
End goal is to level up to a comfy position where you can have enough quality time for the family and personal pursuits, and storing, refining and replicating all the skills learned to one most trusted colleagues. End the sacrifice of having not enough time with the people that matter, with enough skill its easy to adapt to what the world throws at you.
*one of the reasons I'm so pro open source. The barriers guarding this well kept secret is: Time and Attitude. Attributes of only the young and Idealistic.