Really, you'd just want to tax corporations over a certain size that are both highly automated (i.e. high revenue per employee), and have lopsided compensation structures (which could be measured by CEO to median worker pay). If a company successfully automates a bunch of jobs, and then makes that money rain equally on all their remaining employees, I'd have no problem with it. I only think they should be taxed if they try to distribute those gains exclusively to the executives and shareholders.

why would the remaining employees, who have no invested capital into the business (with which the automation is driven by), receive any of the gains from said automation?

The people who invested the capital into the automation reaps the profit. In this case, it's often the shareholders in the end.

Yes, that's how it works today. That's not how I'd like it to work.

Many people here get a significant portion of their compensation via RSUs, ESPPs, and other profit-sharing initiatives, and any company that decides to extend these benefits to lower level workers should be treated favourably by the tax system.