M(faang) where M(faang) is the money/salary over the expected timeline earned from a FAANG-ish company (many many of them), M(su) is the money/salary earned while in a start-up, CV is the Company Value when the Start-Up lotto is cashed in, ES are the Employee's Shares as a proportion of the company that the employee can sell for money, FR is the Fail Ratio of Start-Ups that get to the point that they can sell the company and don't just flame out.
Lets run some numbers to get a feel for the equation:
Say M(faang) is $125k/year and the timeline we are looking at is 7 years; that's $875k total. Say that potential start-up employee is making only $60k per year for those 7 years; that's $420k total. So, the expected paycheck at the end of the 7 years needs to be at least $455k.
So, CV * ES * FR must be $455k. FR is typically said to be 90%, as in 90% of start-ups fail, we'll take that as dogma too and set it to 0.1. ES is likely to be very small, even for very early stage employees, so without nearly any consensus via googling, let's set it at 0.001. CV is the company valuation when the start-up lotto is won, these days it's tough to find this out (it's mostly a power distribution), but let's be a bit conservative and set it at $500M. These numbers give us $50k.
That number is about 10x less than what is needed at a minimum. The start-up fail ratio is really never going to change. So, either the CV must become about $5B, not $500M, or the ES must go upwards from a thousandth to a hundredth (honestly, either situation isn't unreasonable) to meet the minimum pay requirements.
You can play with the numbers yourself and add conditions too (stock mechanics, value of medical benefits, rent issues, taxes, etc), but the math isn't calculus, just nested algebra. Hopefully this will help others out when thinking of trying to join a start-up as an employee.