Given that most equity is worth nothing in the end I don't think you're correct. The beautiful thing about equity is that its future value can not be determined and it's not possible to limit the upside fairly. If employers start putting a cap on the upside, it undermines the shoot-for-the-moon lets make this a $100 billion dollar company spirit that equity otherwise engenders. Had Google had a $1B exit, or a $100M exit - both far more likely scenarios when the chef joined - the grant would have seemed perfectly reason.

This has nothing to do with risk and all to do with incentive. Whether your grant is on top of a full salary or not is irrelevant.