While I agree on your main point, I think that you are confusing marginal tax rate with average tax rate. E.g. the 2017 federal income tax for a single making $300k is in the "$46.6k + 33% in excess of $191k" bracket. This means an average tax of 27.5%. Same for state income tax. So you aren't quite down to $150k/year.

That said, one _does_ face a marginal tax rate of over 50%. So any _additional_ income opportunity is basically cut in half.

On the other hand, an addition expense (but pre-tax) is retirement savings. People in their early-to-mid careers (especially those making $300k/yr) should not be planning for getting anything out of social security.