> you work for FAANG for ~5 years...meet the requirement for an accredited investor...you can invest any disposable income into early stage startups.
if you worked for $300k a year (total compensation) for 5 years, you would have accumulated $1.5m dollars. But you would have an outflow due to cost of living. Let's say it's 50% of your income goes to cost of living. Then you would have only $750k left to invest after the end of your 5 year tenure.
Even if you managed to keep your stock based compensation (rather than selling it), or you picked some other stocks to purchase during your tenure, it's unlikely to have more than a 100% gain. Let's say you did, and end up with a $1.5m pot at the end due to lucky picks.
> You are able to diversify your portfolio across several different startups
A $1.5m is barely enough to invest in one early stage startup these days. And not to mention it's such a small amount that a private equity investment firms/VC firms would likely consider it not really worth the trouble to court you over. So it's likely you have to DIY everything yourself - from finding the startup, to hiring the lawyers and bankers to deal with, as well as learn the domain (which you may or may not already be an expert). Or you will have to take a much more unfavourable term with the PE/VC firms as a small client (you have no influence over the conditions of your investment).