As for the annual bonus, Netflix assumes that everyone is functioning at a high level and pays as if they were making the top-end of the bonus range at other companies. Which is part of the rationale behind the high base compensation.
To me, this is the problem - who determines this and what is their dataset? I worked at a company in the past that claimed to do this, but to do this they generally need some sort of data source. And the data sources for salary data are tough to use in this way - positions/responsibilities vary, regions vary, etc. Just tough to get this right - even with the best intentions.
Source: I have interviewed with them.
I have also not heard any stories about Netflix employees being underpaid, except one being lured away by FB for over $1M.
As an employee, you don't get to see all of the requests for raises, all of the people negotiating salaries, etc. But there's people in the company who do. That's all the data you need.