Otherwise, without being able to objectively measure this then it's all smoke and mirrors and the persons reach these positions through other means.

If that's the case, then taxing an appropriate amount is fair. There's also a precedent with Roosevelt introducing a tax that only really applied to Rockefeller

Either way, I was making a comment on the: 'it's not fair to tax people making obscene amounts because they're actually worth the pay and doing work to match it'. It's basically hard to quantify, it's fair to tax as needed and there is precedent.