the question is often do you have the means to acquire that pre ipo stock. except if you join very early, it's too expensive to buy your stock with the level of risk associated.

as an example, I joined an early stage startup as an exec (potential good deal!), but I would've had to shore 300k to exercise my stocks, pay taxes on it (minimal, that's the huge advantage here), and more than probably see it fail.

now let's play the opposite scenario: you join as an engineer late stage, each ISO might be valued at 10 dollars each. how do you exercise.

this game is skewed towards founders.

in my example, I had to quit for personal reasons and the company was later acquired. however I wan't able to afford, so I got got of $100ks at the time of acquisition.

removing these 90 days time would have let me gain what I was owed.

no hard feelings, because I knew the game, but it was the moment I decided no more startups that have this 90 days BS.