Even if a company exits very successfully, ordinary employees may get almost nothing because of ordinary agreements and conditions for other investors. Dilutions, ratchets, drag, tag, earn-out, black-out, convertibles, preferences, preemptive rights, etc. etc. You may not understand these (I only understand a few); if you do, you don't necessarily know every condition that each other investor is getting; and if you know that, you have no control over future changes.

To be clear, each of these is a quite ordinary business condition with justified business reasons. There would be no intention to harm you, as your employee share is too tiny for anyone to bother over.

But such complications can result in you getting little, even in a big successful exit.