This is not how any of this works.
There’s no such thing as an “elastic model”. Price elasticity is basically a continuum; there are degrees in play. This is a specific game, not “games”, and there are many variables that will impact how it performs and not just the sale price of the game. The game itself has an indeterminate elasticity at this time, as we have no sales data to compare EA sales versus launch just yet (or sales data versus normal price data). Valve probably helped determine the launch price. It is well within the realm of possibility that the game will make more money at $30 than $20.
There is no simple answer, honestly. Just whatever data Valve has and best guesses and some luck