Still, one way to go about this is to assume that workers and employers are rational economic agents and look at their incentives and bargaining power. Obviously, an employer will never employ anyone for more money than they believe that employee will contribute to the company (assuming no nepotism, fraud, corruption etc). However, an employee may well accept to work for less money than they are actually contributing, since they have ~0 visibility into this number, and much less bargaining power than the company, especially at the lower end.

So, in for a large company without powerful unions, we can virtually guarantee that employees are each receiving less money than they are actually contributing - with shareholders correspondingly receiving more money from the profits accrued. Additionally, shareholders also have more money based on how over-valued a company's stock is, which employees gain nothing from.

Now, the real question is of course "how much more wealth are they getting from the company"? I don't have an exact answer to this question. However, one way to look at it is that Amazon has ~800k employees who at MOST could collectively own the ~20% of amazon stock on the open market, while Jeff Bezos owns ~10% of the company directly. This would mean that Jeff Bezos personally would have to contribute as much as ~400k people to the company for his contributions to be in line with the value he extracts. I just don't believe that Amazon could be where it is if it replaced ~400,000 employees with a second Jeff Bezos. Honestly, I don't believe that Amazon could be where it is if it replaced 1,000 employees with a second Jeff Bezos.