That's not true at all. All i have in a bachelors and i do very fine. I know many in my position. A graduate degree doesn't replace experience, unless it's combined with work and you are working on cutting edge stuff. But it's highly dependent upon field and industry. Naturally for engineering you need a higher degree to climb, but that's always been the case. If you are in something analytic - yes, but for everyone else - the good ole bachelors will suffice in corporate america.
How long have you been an engineer? Because starting salary is not equivalent to total salary. The reason engineers get paid so much right now because there is a demand. However, as soon as your industry (petroleum, computer, etc.) slows down, they lay off all the high paid engineers. When the market comes back, they go and hire NEW engineers straight from college. Because of this, entry level engineering pay is high, but after so many years it flattens out and you top out. The only way to make more money is to go into management or change careers. You should see all the former engineers in law school, trying to become patent attorneys because their engineering careers had topped out. The message here is don't spend all those big paychecks. You're getting paid more not because you're so smart, but because your job is incredibly insecure. Learn to make yourself irreplaceable, or prepare for long bouts of unemployment when your field takes a downturn. What do you think is going to happen to all those petroleum engineers if the price of oil is really a bubble?
This is why I like the Sarbanes Oxley Act, AKA the accountant full-employment act. For years they've been knockin down doors trying to get accountants.