It is nice to have some “survey” say that open source develpers earn MORE. For the sake of the credibility of the survey, let’s hope it was not “funded”. We all know very well how the proprietary world vendors pay for surveys to show how wonderful they are :-).
But having said all of that, I think it is real. An RHCE is paid much more than a MCSE, or so some independent surveys say. Why? The RHCE courses and certifications are performance based. Not multiple choice, pointy clicky stuff almost all the others (other than Cisco) has. If you do not know your stuff, you are out. Add that to the fact that a RHCE/T can manage about 10:1 more systems than a equivalent MCSE, means even if you paid an RHCE twice a MCSE, you get a person who can manage 10 times of the systems a MCSE can. That gives a significant amount of value to the organization. So, instead of hiring 10 MCSEs to manage 100 machines, you need just 1 RHCE to manage those same machines.
In case you want a sponsored point of view, read this.