That is not entirely true. Look at UPS they used the current fleet make up to decide which aircraft was the average of it's fleet, then based the pay rate off the productivity of that airplane. So productivity was part of that equation.

What I think this boils down to is more of "how dare someone else get paid as much as me". It is so prevalent in this industry that pilots feel the need to have "something" more than someone else. You hardly ever hear, "good for them". You never hear lawyers or doctors complain about what someone else in the profession makes. Sure some of it comes from the fact that we pattern bargain, and yes we should raise when we can. It just appears we are more concerned about making sure others get less, than making sure as whole we all get more.