What's "valid" isn't a matter of immutable natural law. Clearly there are some contributors to startups---founders and early investors---who demand and get low

What's "valid" isn't a matter of immutable natural law. Clearly there are some contributors to startups---founders and early investors---who demand and get low-probability, high-reward financial bets that can, albeit probably won't, pay off big. Whether that bet is available to others, and to what extent, is a matter of choice. If you've got something valuable to offer, and want founder-like exposure to risk and reward, negotiate a founder-like equity package. If they won't give it to you, it's not because they're a startup. It's because they're unwilling to give it to you. Perhaps they don't think you're worth it. Perhaps they just don't want to share the pie like that.