It doesn't matter whether production methods that do not produce pollution can be developed in the future. Because there are currently no methods that do not produce pollution, the corporation might be doing all that it can now, even if better methods are developed later.

The CEO’s argument doesn't rely on causal reasoning. Instead, the CEO assumes that her corporation is doing all it can to reduce pollution.

The CEO only addresses the specific criticism that her corporation is not environmentally responsible. She argues that this criticism is false, but never generalizes about any other criticisms.

The CEO doesn’t assume that the corporation has succeeded in reducing the amount of pollution it produces, she explicitly states that it has. She says, “Our current production methods pollute significantly less than our old methods did.” So the corporation did succeed.

To be environmentally responsible, the corporation must be doing all that it can to pollute less. If there are production methods that would allow the corporation to produce less pollution than it does now, then it isn’t doing all it can and it isn’t environmentally responsible.