Well first, I'm not talking about pay necessarily, though executive compensation is (IMO) out of control. I was more referring to the intangible "respect" afforded to decision-makers (aka "leaders").
As far as pay goes, you can say they have a "big impact" all you want, but that's not how any other labor market works: it doesn't matter how much value my labor provides. Plumbers are paid the same to fix the toilet in the Louvre as they are at the gas station down the street from it. Leverage or no, my salary is determined by how little other, similarly skilled people are willing to take. If you can find somebody as skilled as Nadella in the technical skill of managing a software company, but for much less money, then you should either hire that other person or make Nadella take the lower salary.
But again, I'm not talking about money. These corporations have shareholders, and the shareholders are free to overcompensate whichever of their employees they choose too, even the C-suite. My point is that we revere "leaders", our "history" classes (unless you actually study history at a univesity) are mainly hagiographies of past "leaders," and every societal norm tells us that "leadership" is this powerful, ineffable magic. It's not. There's no such thing. Some people are in charge. They might even be powerful. They might get incredible things done. That doesn't mean that people who could have gotten the same things done given the same power or leverage are scarce.
Management is a technical speciality, probably one that's less difficult than, say, being a good welder. We pay good welders tons of money too. I'm not trying to say either is overpaid. I'm just trying to say "leadership" (i.e. directing the work of others, business strategy, and decision-making) is over-valued in terms of respect and esteem.