I have no idea what the janitors or security guards in my organization make. If I found out they made a similar salary to me, my response would be, "awesome! I'm glad my organization values all its employees."
If you're a high-skill employee and are making a similar salary to low-skill employees, ask yourself two questions:
1. Would you rather do the low-skill job? If so, great! Apply for that job as soon as there's a vacancy.
2. Could you make more money elsewhere? If so, great! Start applying for other jobs.
If the answer to both questions is no, what's the problem? Other people's success doesn't take away from yours. And, in my experience, high-skill jobs tend to have a lot of intangible benefits that low-skill jobs don't have - flexibility, variety, autonomy, prestige, etc., so it's not true that you went to engineering school (for example) for nothing.