Earlier quoted context omitted.
Because that’s the racket! They can’t pay you top dollar because they’re a lean startup, so they make up for it by adding “equity” to remuneration. But that equity is in the form of options which you have to buy with your not-top-dollar salary, so it’s unlikely you will. Then you leave the company before an event and those options expire after a month or so, going back into the pool for another engineer to do the sam…
its not done this way because the founders want to screw you, its done this way because of a bunch of arcane tax laws. Its complicated to explain, but the origin of all of these weird "options not equity" and "90 days to expire" type things are because of US tax law. If the startup could give you shares without putting the employee and the company both in a very puntantive tax situation they would.
I sent a Section 220 demand letter to the founders of this company to get transparency on the money that was taken during the secondary stock sale and they're currently fighting me on it because I wasn't a shareholder at the time the secondary sale took place, I only held options in the company at the time.
This anecdote is illustrating a real world situation in which it is being used as a way for founders to try to screw their employees, not because their hands are tied by some arcane tax law.