Executives get that kind of salary because their tenure is short, they are under pressure, and they are (at least in theory) held accountable for performance by multiple stakeholders (employees, shareholders, the board, customers, etc). Members of Congress have a sky high re-election rate, have a much less stressful lifestyle, and are generally not held to such an account for their activity. We want to disincentivize choosing politics as a career, not encourage it.