I've never heard it adequately explained why employees should accept this state of affairs. Not only is the cap table invisible, but the fully-diluted cap table and terms of dilution and many other terms and conditions are also hidden from non-founders/investors at most startups I've read about. I've heard so many stories of shares getting diluted right out from under employees immediately before a liquidity event that it has become a trope. IMHO that's not investing into a startup; that's buying a lottery ticket.
What am I missing here about typical startup stock options where the same terms and conditions founders and investors see are not accessible to employees?