Not withstanding card counting or other AP techniques, the house advantage pertains to the rules of the game as a whole, not dependent on how much you wager. Of course, each situation you are presented with (e.g. 7 vs. dealer 9) has a different expected edge, but those all fit into the overall house advantage depending on how the game is offered.
Basic strategy gives the player the lowest house advantage without using AP techniques, and that is because it has prescribed the best move for the player in any situation based on the rules of the game, but not based on what cards are left in the deck/shoe.
Using card counting systems or other techniques can either decrease the house advantage or even give the player an advantage (that's what we're all after around here, right?) by tracking the changes in advantage as the deck/shoe is played out. That's why there are both betting strategies and basic strategy deviations related to the count.
good luck
[And yeah, what Sonny said too]