If you put a cap on it, then you'll run into a minor problem.
Being a doctor, lawyer, engineer, scientist, or any position like that takes one hell of a lot of time and effort (and often a big initial investment as well). Plus the work is a lot harder. Sure, some people would still want to do those jobs, but there comes a time when it just isn't worth it for most people. Can you honestly tell me that if you were a doctor, you would be on call 24/7, work 12+ hours a day, have a very hard job where one screw up could cost a life, and do it all for the same pay as a guy who has an office job filling in spreadsheets? Because that is what this would equate to. The seniority required to get that level of pay in an office job is offset by the extra years of school a doctor has to go through, as well as the residency period.
Some jobs simply need more pay than others, and for some jobs, that pay is above the $100,000 mark. Hell, for some jobs, it's above the $1 million mark. Setting an arbitrary cap and having all money earned after that get taken away will do nothing but harm those in higher positions, and encourage them to take easier jobs that pay the same, leaving important and difficult jobs vacant.