There's a huge difference from getting stock grants from FAANGM and getting options from startups, which may easily turn into funny money. The recent underwhelming tech IPOs from Uber, and perhaps worrying upcoming IPOs from AirBnB, indicate that even options from unicorns might be of debatable worth. It's just not money in the bank in the same way those from the tech giants are.

I think a lot of people, myself included, don't know the nominal value of their total compensation. If their employer pays the full costs of their health insurance plans, I don't think many people know what those costs are.

Also, as others have pointed out, certain components of total compensation, like various forms of 'equity' in the employer company, are not reasonably equivalent to cash, and no one could feasibly evaluate the cash value at any particular moment in time given all of the relevant variables needed to even estimate those cash values.

Because Cash is king. Everything else can be taken away or reduced or diluted or what not.